Banana Walnut Cake with Mocha Buttercream

This little cake deserves a recurring spot on your fall baking schedule for sure.   You don’t need a special occasion to make it…and apart from the generous lashing of mocha frosting I consider it very wholesome.   Have a piece as a mid-morning pick me up, and  share the rest with the kids after school.  This cake has mysterious restorative properties.  Which might, or might not, have something to do with a shot of espresso.

THE BEST Banana Snack Cake with Mocha Frosting

The dark mocha frosting takes a great little banana cake and makes it an even greater little banana cake.  In the recipe development phase my original plan was to make an espresso buttercream.  But when I got right down to it, my hand reached for the box of Valrhona cocoa powder and did the deed with a full 1/2 cup of the stuff.  The combination of banana and chocolate is powerful and I couldn’t resist going for it again.  My BANANA CAKE WITH NUTELLA BUTTERCREAM is one of my favorites.

Mocha Buttercream

Did I mention that the cake is a one bowl deal?  I’m trying to do that whenever possible, I think it makes a huge difference.

Banana Walnut Cake with Mocha Buttercream

Yield: serves 9


  • 2 very ripe bananas
  • 2 large eggs
  • 3/4 cup sugar
  • 1/2 cup brown sugar, packed
  • 1/2 cup vegetable oil
  • 1/2 cup buttermilk (or yogurt)
  • 1 tsp vanilla extract
  • dry ingredients
  • 2 cups flour
  • 1 tsp baking soda
  • 1/4 tsp salt
  • a heaping 1/2 cup of walnut halves
  • Mocha Buttercream Frosting
  • 4 Tbsp unsalted butter, at room temperature
  • 3 cups confectioner's sugar
  • 1/2 cup unsweetened cocoa powder
  • 1 tsp instant espresso powder
  • 1/2 tsp vanilla extract
  • heavy cream or milk for thinning


  1. Set the oven to 350F
  2. Begin by toasting the walnuts. Spread out the nuts on a dry baking sheet and put in the oven for 10-15 minuted, just until you can smell their aroma and they have crisped up. Watch carefully, and give the pan a shake or two during toasting. Let cool before chopping.
  3. Mash the bananas in a large mixing bowl. Be sure to get all the lumps. Beat in the eggs and the sugars, and then add the oil, buttermilk. and vanilla. Blend well.
  4. Sift the dry ingredients right into the bowl, and fold in lightly, just until everything is blended. Fold in the nuts.
  5. Spray a 9x9 square baking pan with cooking spray, and line it with parchment if you want to be able to life the cake out for clean frosting. Turn the batter into the pan and bake for about 45 minutes, or just until a toothpick inserted in the center comes out without wet batter clinging to it. Don't over bake.
  6. Let the cake cool before frosting.
  7. To make the frosting, put the soft butter in a large bowl (use the same bowl, just give it a rinse and dry it.) Blend in the espresso powder, and then sift one cup of the sugar and the cocoa powder on top and begin to beat, slowly at first. Sift in the rest of the sugar while beating, along with enough cream to thin the frosting to a spreadable consistency. Add the vanilla and beat until everything is smooth.


The cake portion of this recipe is adapted from Ina Garten

Banana Walnut Snack Cake with Mocha Buttercream 3

Banana Walnut Snack Cake with Mocha Buttercream

This isn’t the time to deny yourself, it’s Friday!


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19 Responses to Banana Walnut Cake with Mocha Buttercream

  1. Gale says:

    Can you use butter instead of oil in the cake? How much butter?

  2. This bread looks fabulous! I want to inhale it with all of its buttercream goodness!

  3. To me this is coffee cake with frosting—which is great. It’s a ‘no big deal’ to put together type of a cake. Often when I make a coffee cake, it is spur of the moment. Like hey wouldn’t be great to find this sitting next to the coffee pot in the morning. Plus it uses those bananas that get away from me.

    • Sue says:

      I agree, it’s the only kind of cake I really enjoy making, and definitely breakfast cake with benefits is the way I’d describe it!

  4. Delicious! The mocha buttercream makes this banana cake particularly tempting.

  5. Mary says:

    Sold :-) I have to give this a try. It sounds fabulous. Hope all is well. Hugs and blessings…Mary

  6. Wow wow wow, this looks incredible. My banana bread has never looked so boring – ha! Mocha buttercream is the best thing ever. have a great weekend!

  7. Catherine says:

    Such a beautiful and tempting looking cake. Perfect for a good cup of coffee. Blessings, Catherine

  8. That mocha buttercream looks divine, what a perfect fall cake!

  9. cheri says:

    What a special cake Sue, love the flavor combination!

  10. Susan says:

    I know I would love this cake – even without the frosting!

  11. sippitysup says:

    Strange but true. This very AM I was cleaning out the freezer and came upon a single disc of cream cheese pie dough that I’d made a couple months ago. I decided it needed to be used today or tossed. So I thawed and rolled it and set it to chill again. Meanwhile, I decided to crawl through an old Food & Wine cookbook of my mom’s from 1989 for inspiration. I came across a Banana and Walnut Tart that intrigued me. I came within centimeters of deciding to make that tart when I remember all the “foraged” figs I had on the kitchen window sill. So I went with Raspberry and Fig instead. But I was so close to stealing your idea (without knowing it). You’ll see that tart as soon as the weather “autumns up” here though. GREG

  12. ahu says:

    This is beautiful … Recipes like this makes me wish I weren’t allergic to walnuts! *cries*

    • Sue says:

      Oh that’s too bad, my nephew is deadly allergic to nuts and I always think about allergies when I cook with nuts. Luckily this cake is all about the buttercream, so just leave the offending nuts out!

  13. Dom says:

    really beautiful… I particularly like the sound of the buttercream… I always pop over to your blog when I need inspiration for toppings. Thank you!

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