Chocolate Walnut Potato Cake with Chocolate Ganache Frosting

Just when you think there are no more original potato recipes to be made, along comes 40-plus bloggers to save the day.  The new potato recipe day, that is.

The rules for participating in this challenge were simple.  Use any kind of potato you wish, but you must create an original dish.  And, no…..we didn’t have to be a poet to participate.  That’s just a bonus.  LOL.

Ultimate Recipe Challenge | Potatoes | The Chelsea Project |

As for the potato recipe, I immediately knew the one I wanted to use.  You see, back in the day, my mom was one of the best cooks in the county.  Ask anybody in our small town and you’ll surely get an ear full.   They’ll just go on and on about her cakes, pies, and sweet tea.  

But that was a long time ago and mom doesn’t bake anymore.  In fact, when she moved to assisted living, I brought all of her old recipes home with me.

Vintage cookbooks | The Chelsea Project |

One day, as I was thumbing through the box, it broke my heart to see how the pages of every book were crumbling and the words….fading.  Over the years, Mom had made these recipes thousands of times.  Anytime there was a church social, family gathering, funeral, wedding, or sickness.  Mom’s delicious dishes were always there.  So I knew that somehow, though the pages are now failing, the memories had to be alive and well.  ……They just had to be.  

Chocolate Walnut Potato Cake with Chocolate Ganache Frosting | The Chelsea Project |

So, I put out a little feeler on social media to see if anybody in my hometown would be interested in having a copy of mom’s old recipe.  The response was amazing.  

And so, the deciphering began.

I pulled what I could from the scribbles on the crumbling brown notepad and the rest from my own memory of hanging with her in the kitchen.  The result is this super-delicious dark chocolate cake made with leftover mashed potatoes.

Chocolate Walnut Potato Cake with Chocolate Ganache Frosting | The Chelsea Project |

But, before we head over to the recipe card, let’s do a quick run-though just so you can see how this cake comes together in the bowl.

First, you’ll want to bring all of the ingredients to room temperature, then combine the wet ingredients together (butter and sugar first), followed by the dry ingredients.  After all ingredients are mixed together, including the finely chopped walnuts, the batter will be quick-whipped to the texture of a mousse.  The key is to add air to the batter very quickly without over beating, so please, please… kick the mixer to high and let’er rip.  The batter should change from a batter texture to a near-mousse texture rather quickly (in about 30 seconds or less).  Then, immediately transfer the batter to the baking pans and pop them into the pre-heated oven.

Chocolate Walnut Potato Cake Mixing Steps | The Chelsea Project |

Chocolate Walnut Potato Cake with Chocolate Ganache Frosting
Serves 10
A delicious dark chocolate cake filled with walnuts and spices and frosted with a rich chocolate ganache.
Write a review
Prep Time
1 hr
Cook Time
1 hr
Total Time
2 hr
Prep Time
1 hr
Cook Time
1 hr
Total Time
2 hr
For the cake
  1. 1 cup butter (2 sticks)
  2. 2 cups sugar (granulated)
  3. 1 & 1/3 cups leftover mashed Idaho or Russet potatoes (creamy, not stiff)
  4. 4 eggs (well-beaten)
  5. 3/4 cup buttermilk
  6. 2 cups self-rising flour (White Lilly or other soft wheat flour)
  7. 3/4 cup baking cocoa
  8. 1/2 teaspoon cinnamon
  9. 1/2 teaspoon nutmeg
  10. 2 teaspoonfuls baking powder
  11. 1 teaspoonful baking soda
  12. 1/2 cup walnuts (finely chopped)
  13. 1 cup of raisins (optional)
  14. 1/8 to 1/4 teaspoon ground cloves (optional)
For the ganache
  1. 1/2 cup butter (1 stick)
  2. 1 and 1/2 cups sugar (granulated)
  3. 2 heaping tablespoonfuls baking cocoa
  4. 3/4 cup Half and Half
For the cake
  1. Bring all ingredients to room temperature.
  2. Pre-heat oven to 350 degrees.
  3. Prepare baking pans.
  4. Once the mixing is started, work quickly to get the whipped batter into the oven.
  5. Cream butter and sugar until fluffy.
  6. Add mashed potatoes.
  7. Add eggs.
  8. Add buttermilk.
  9. Using the gentle speed of the mixer, fold in the flour 1/2 cup at a time.
  10. Fold in the cocoa, cinnamon, and nutmeg.
  11. Fold in walnuts.
  12. Add the baking powder and baking soda.
  13. Turn mixer to high and whip the batter to a mousse-like texture (about 15-30 seconds).
  14. Carefully scoop batter (so it isn't deflated) into baking pans (makes 2 - 9-inch layers or 3 smaller - 8-inch layers).
  15. Immediately place all pans into preheated oven.
  16. Bake until done, about 30 minutes for 9-inch pans and 20-25 minutes for 8-inch pans.
For the ganache
  1. Melt butter in a stovetop pan.
  2. Stir in sugar and cocoa.
  3. Stir in Half and Half.
  4. Bring to a soft boil and stir constantly.
  5. When mixture thickens slightly and sticks to the spoon, remove from heat.
  6. Add ice cubes to a heat-proof bowl.
  7. Set pan holding the ganache onto the ice cubes and stir constantly.
  8. Assemble the cake when the ganache is cooled, but still in a syrup consistency.
  9. The ganache will thicken to a hot-fudge consistency when fully cooled.
  1. When cake layers are done, remove from oven and let cool in pans about 5 minutes. Then turn the layers out to cool on a rack.
  2. If the mashed potatoes are too stiff (dry), the cake can be a little dry. To prevent dryness, after the cake is cut, seal two slices of fresh bread with the cake in the cake container.
  3. A quick short-cut is to bake the cake in a 9 by 13 sheet-cake pan. When cool, poke holes in the cake with the end of a wooden spoon and pour the ganache over the cake so that it fills every hole.
  4. During the holidays, mom added 1 cup of raisins (soaked in water for 30 minutes and then drained) and 1/8 to 1/4 teaspoon cloves. These are folded into the whipped batter along with the walnuts.
Adapted from Mom's Personal Collection
Adapted from Mom's Personal Collection
The Chelsea Project
 And, there you have it.  A chocolate cake made with leftover mashed potatoes.

Who knew?

If you enjoyed this recipe, I do hope you’ll save it for later and share it with your friends.

Chocolate Walnut Potato Cake with Chocolate Ganache Frosting Collage | The Chelsea Project






  • Reply thekimsixfix March 9, 2016 at 6:18 am

    Who knew you could make cake with potatoes? Awesome!

    • Reply theChelseaProject March 9, 2016 at 8:34 am

      Thanks, Kim. This was a super fun recipe to pull together.

  • Reply Patti Estep March 9, 2016 at 6:56 am

    Hi Susie,

    This looks fabulous! What? Potatoes in cake? Super interesting and I can see how it would make the cake moist. I loooove chocolate and definitely want to try this one.
    Thanks for sharing.

    • Reply theChelseaProject March 9, 2016 at 8:35 am

      Thanks, Patti. It really is a classic. Hope you enjoy!!

  • Reply Jann from Newton Custom Interiors March 9, 2016 at 8:00 am

    Susie, I’ve been wondering how you added potatoes to make this cake. Ingenious! It looks delicious! Love the story about your mom too. So special that you have her recipes.

    • Reply theChelseaProject March 9, 2016 at 8:37 am

      Thanks, Jann. As Southerners, we love our potatoes……even in our cakes. Lol.

  • Reply 1915house March 9, 2016 at 9:22 am

    This looks delish!!! Can’t wait to try- I think my boys would love it!

    • Reply theChelseaProject March 9, 2016 at 9:27 am

      Thanks, Sarah. Yes. I haven’t met anybody who didn’t like chocolate cake. 🙂

  • Reply SheilaG- Plum Doodles March 9, 2016 at 9:35 am

    Oh, wow, this cake looks amazing! I can’t wait to give it a try- hopefully, gluten-free flour will work. 🙂

    • Reply theChelseaProject March 9, 2016 at 9:41 am

      Thanks, Shelia. I surely hope it does, but I’ve never used this flour. You know us Southern cooks love our soft wheat flour and don’t venture away from it unless we have to. Please let me know how it turns out. If you like, I can add your link to mine offering a gluten free version.

  • Reply mylifecookbook March 9, 2016 at 10:35 am

    That’s wonderful that you are making your mom’s recipes. I have a big bag of my mom’s recipes that I should go through. Most I do by memory. Anyway this looks unbelievable … chocolate….love cake….and love that you used potatoes! So creative.

    • Reply theChelseaProject March 9, 2016 at 11:22 am

      Thanks so much. To this day, it’s one of my very favorite cakes. Hope you enjoy it, too.

  • Reply shelstring March 9, 2016 at 12:36 pm

    I’m always adding different things to my cakes to create the texture I want, I can’t wait to try this. Regardless, I know my family will be in HEAVEN over it!! 😉

    • Reply theChelseaProject March 9, 2016 at 2:30 pm

      Thanks so much. I do hope you all enjoy the recipe.

  • Reply Jeannie @ For what it's worth March 9, 2016 at 2:53 pm

    This recipe excites me and I can’t wait to try it out. Pinned, because I’m sure I’ll make it more than once

    • Reply theChelseaProject March 9, 2016 at 3:05 pm

      Thanks, Jeannie. Mom would be so happy to know you are enjoying the recipe. Let me know how it goes. Hope you love it!! XOXO

  • Reply Teri@The Freshman Cook March 9, 2016 at 5:13 pm

    What a wonderful story! I love old family recipes, and it sounds like you have a treasure trove of food and memories in your notebooks! Your cake looks amazing!

    • Reply theChelseaProject March 9, 2016 at 6:57 pm

      Thanks so much, Teri. Yes, I have found so many recipes that I plan to decipher. I do hope you enjoy the cake. It’s like sharing a bit of my family with yours. XOXO

  • Reply homemadezagat March 9, 2016 at 6:23 pm

    Never ever would I have thought of this cake with potato. It looks really good too. Must try this

    • Reply theChelseaProject March 9, 2016 at 6:59 pm

      Thanks so much. Well, you know us Southerners…we will put potatoes in just about anything. LOL.. Enjoy!!

  • Reply This Ole Mom March 9, 2016 at 8:29 pm

    Woah! Potato in cake who would have thought! It looks so good.

    • Reply theChelseaProject March 9, 2016 at 9:48 pm

      Thanks so much. It’s one of my family favs. Thanks for stopping by!!

  • Reply Mary March 9, 2016 at 8:53 pm

    Oh my, this looks so delicious and what a unique recipe. I’ve never had cake with potato. Pinning this one!

    • Reply theChelseaProject March 9, 2016 at 9:51 pm

      Hi Mary and thanks so much. It’s one of my family’s favorites. It doesn’t last long around here. LOL.

  • Reply terristeffes March 9, 2016 at 9:08 pm

    Soooo, ok, we could be best friends. I wasn’t born in the south, but this sounds like something my gramma would make. I cannot wait to try it!

    • Reply theChelseaProject March 9, 2016 at 9:53 pm

      Yes, stick with me, Terri. We will be BFFs….. because I have a pile of mom’s old recipes that I will figure out and get posted. Thanks so much.

  • Reply Ann Butler March 10, 2016 at 1:08 am

    This looks amazing…I have to try this recipe!

    • Reply theChelseaProject March 10, 2016 at 1:43 am

      Hi Ann. Thanks so much. Hope you enjoy!

  • Reply Susan Moncrieff March 10, 2016 at 8:40 am

    This cake looks so good! I think I’ll make it for my family this weekend! Love the old recipes. They have been made with love over the years. So nice that you can continue making your Mom’s old recipes!

    • Reply theChelseaProject March 10, 2016 at 7:07 pm

      Thanks, Susan. I hop you and your family love the recipe and enjoy it for many years to come.

  • Reply Elaina Newton (@TheRisingSpoon) March 10, 2016 at 11:54 am

    What a cool way to use up leftover potatoes! I was just reading a post earlier this week from a gal who bought 50 lbs. of potatoes and was coming up with ways to use them (mostly freezing them for hash browns). Maybe I should pass this along to her! Your cake looks so yummy! 🙂

    • Reply theChelseaProject March 10, 2016 at 7:09 pm

      Hi Elaina and thanks so much. I believe the cake freezes really well. I remember Mom freezing the individual cake layers, defrosting, and then stacking them on the cake plate with the ganache.

  • Reply Karen @ Dogs Don't Eat Pizza March 10, 2016 at 10:27 pm

    First of all, YUM! That looks amazing! Second, what a wonderful tribute that you are working on her recipes. I just loved that. Pinned – can’t wait to make it!!

  • Reply Mary Beth @ Cupcakes and Crinoline March 11, 2016 at 2:05 pm

    Oh my word! Chocolate and potatoes – this looks so rich and moist. I am pinning to try later!

    • Reply theChelseaProject March 11, 2016 at 4:00 pm

      Thanks so much, Mary Beth. I hope you can make the cake often and enjoy it with people you love. XOXO

  • Reply Bluwatergal March 19, 2016 at 9:34 pm

    This looks delicious! Family recipes are always a treasure. Thanks for sharing! Bwg ~~~

    • Reply theChelseaProject March 21, 2016 at 7:51 am

      Thanks so much! Yes, Mom’s recipes are certainly special. I hope to share more as the challenges continue.

  • Reply 3 Things My Mother Taught Me - The Chelsea Project November 3, 2016 at 3:14 am

    […] simply turn the leftovers into a delicious chocolate walnut potato cake with a ganache frosting (link here). Yes! A chocolate cake made with […]

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