Gluten-Free Banana Cake with Peanut Butter Penuche Frosting

Gluten-free cakes are an interesting thing to tackle.  So many different gluten-free flours create such different results.  I’ve found that I don’t like to use all “white” flours–sweet (glutinous) rice, tapioca, potato or cornstarch.  I like to use sorghum in large proportions because I think it mimics wheat flour better in the baked cake.  That goes for cookies, quick breads, and biscuits too.  Buckwheat is probably my favorite gluten-free flour.  It has such a great, assertive flavor.  But it’s not always what you want in certain recipes.  It can take over.  I only use it in specific cases, like the Gluten-Free Vegan Linzer Cookies I made during the holidays.  Perfect with the nuts in the cookies. I used it in this gluten-free banana cake because I knew it would give the cake a moist, dense texture more like a regular cake made with wheat flour.

I was a little worried the buckwheat and banana flavors would clash.  But they were very nice together and I really liked the way it turned out.  With the frosting…man, it’s so good.

I’ve been working on perfecting the recipe for this frosting.  Sometimes it is indeed perfection.  And sometimes it doesn’t quite turn out exactly how I was hoping.  I haven’t quite figured out how that works when I use the same ingredients and directions.  When I get it just right, it sets up like the creamiest fudge you can imagine.  Like penuche, in fact.  When it doesn’t quite set up, it still tastes fabulous, the texture is just more like regular old frosting.

But it doesn’t matter all that much because it always tastes the same–kind of like Reeses Pieces.  And that is a good thing, I promise you.  I have loved those ever since I was a little girl and had them when my parents took me to see E.T.   

The combo of browned butter, brown sugar and peanut butter is magical.

The cake I made was not vegan.  But I’ve included the appropriate substitutions in the directions to make it vegan.  (I was out of vegan equivalents and a little slice didn’t bother me too much.)  The frosting will still be good without the browned butter.  (Almost as good.  There’s no vegan equivalent for browned butter unfortunately.)

This recipe also makes great cupcakes–24 to be exact.  I made them for Teacher Appreciation Day at my daughter’s school.  I heard they were a huge hit. :)  I took a non-GF version of this cake to a party with friends and it was well received.  As for my children…they devoured this cake in three days. My son said, and I quote, “Mom, this is the best frosting EVER!”  I have to agree.

clock clock iconcutlery cutlery iconflag flag iconfolder folder iconinstagram instagram iconpinterest pinterest iconfacebook facebook iconprint print iconsquares squares iconheart heart iconheart solid heart solid icon

Gluten-Free Banana Cake with Peanut Butter Penuche Frosting

Buckwheat adds a nice texture and flavor to this gluten-free banana cake. The peanut butter frosting is absolutely scrumptious.

  • Total Time: 1 hour
  • Yield: 10-12 1x


Units Scale
  • For banana cake:
  • 1 1/4 cups granulated sugar
  • 1 cup buckwheat flour (or 2 1/2 cups all-purpose wheat flour for all of the gf flours)
  • 1/2 cup sweet (glutinous) rice flour
  • 1/2 cup tapioca starch
  • 1/2 cup sorghum flour
  • 1 1/2 tsp. baking powder
  • 1/2 tsp. baking soda
  • 1 tsp. salt
  • 1/4 tsp. xanthan gum (omit if using wheat flour)
  • 1/2 cup cool or room temperature butter (use vegetable shortening or Earth Balance for vegan)
  • 1 cup mashed banana (from about 2-3 really ripe bananas)
  • 2/3 cup sour cream (for vegan use sour cream substitute, non-dairy yogurt or soured non-dairy milk)
  • 2 large eggs (for vegan use flax eggs or egg replacement powder)
  • 1 tsp. vanilla extract
  • For frosting:
  • 6 oz. salted butter (for vegan, use Earth Balance)
  • 1/2 cup brown sugar
  • 1/2 cup peanut butter
  • 4 cups or more powdered sugar
  • 1 tsp. vanilla extract
  • milk or water, about 1/4 cup


  1. For banana cake: Preheat oven to 350 degrees F. Grease two 9″ round cake pans and dust with a little buckwheat flour. Line the bottom of each pan with a round of waxed paper or parchment.
  2. Sift the dry ingredients together into the bowl of a stand mixer, or large mixing bowl if using a hand-mixer.
  3. Whisk together the banana, sour cream, eggs and vanilla extract. Set aside.
  4. Add the butter to the dry ingredients and turn mixer onto low. Mix just until butter is in small pieces. (It will look like when you’re making biscuits.)
  5. With the mixer running, add the banana/sour cream mixture. Beat on medium speed for about 2 minutes. Scrape down the sides of the bowl and turn mixer on for a few more seconds. Divide batter between the pans, smooth the top, and place in oven.
  6. Bake for about 30 minutes, or until the tops spring back when lightly pressed and a cake tester inserted into the center comes out clean.
  7. Let cool in the pans for about 10 minutes, then carefully run a thin knife around the inside of the pan to loosen the cake and turn out gently onto a cooling rack. Let completely cool.
  8. For frosting: Melt butter in a pan and let cook until the butter turns golden brown and smells wonderful. (If using vegan butter, just let it melt, don’t try to brown it.) Remove from heat so it doesn’t burn. Add the brown sugar. It will bubble up a bit. Stir until the brown sugar is dissolved. Add the peanut butter and stir well. Let sit for a few minutes until just barely warm. Transfer to a large mixing bowl and stir in vanilla.
  9. Using an electric mixer, beat in the powdered sugar, alternating with a little milk or water. Beat on high speed until the frosting is very thick and starts to set up like fudge. (It might start to look like it’s separating, add a little more powdered sugar and milk and keep beating.) If the frosting hasn’t set up, chill it for about 15 minutes in the fridge and beat again.
  10. To assemble cake:
  11. Remove the waxed paper from the first cake layer and place it on a serving platter. Top with about 1/2 cup of the frosting and smooth it out with an icing spatula to the edges. Top with the next layer. Place in the freezer for a few minutes so the icing can set.
  12. Place more of the frosting over the top of the chilled cake and use the icing spatula to spread it to the edges and down the sides of the cake. Turn the cake around while holding the spatula against the side of the cake to create a crumb coat. Chill again for a few minutes in the freezer.
  13. Spread the rest of the frosting (you might not need all of it) over the cake for the final layer. Let chill until ready to serve. (Any leftover frosting quickly disappears spoonful by spoonful.)
  14. Makes one 9″ round cake, 8-10 servings.
  • Author: Lindsey Johnson
  • Prep Time: 30 mins
  • Cook Time: 30 mins
  • Category: Dessert
  • Cuisine: American


You may also like


  1. I haven’t done any gluten free baking, but I’m betting that this cake is so delicious just as is. And that frosting sounds like heaven!

  2. I love anything buckwheat, and this cake looks superb! I make GF banana buckwheat pancakes – love that combination. Just found your site via Tartelette and am greatly enjoying the recipes. Looking forward to reading more, and to giving this cake a try.

  3. Excellent recipe. I have the BH&G cookbook and am always looking for ways to adapt their recipes. I used millet flour instead of buckwheat and coconut oil instead of butter. They turned out fantastic. Thank you!

  4. I want to make this cake into cupcakes, but I’m wondering: do you use raw buckwheat flour? Roasted buckwheat is actually the more common one apparently. I guess I just need to know what brand you use. I grind my raw buckwheat groats up.

    1. Hi Violet! That’s a great question. I usually just use the organic buckwheat flour from Bob’s Red Mill. To be honest, I’m not sure if that’s the toasted or raw. I assume either will work. I have used raw buckwheat groats for other things, but I haven’t ground them into flour. I think the only difference as far as the cake is concerned is the taste of the roasted vs. raw.

  5. Love buckwheat, and I made this cake a few days ago. Thanks for the recipe, turned out great. A couple questions: mine turned out a little dry, is there anything I could add to the recipe to make the cake more moist? Add another egg? Also what if I wanted the buckwheat, but it didn’t matter if it’s gluten free? Can the other flours be wheat flour? Or split the buckwheat and wheat flours 50/50? Thanks again.

    1. Hi Greg! I’m so glad you made this cake and enjoyed it! Just based on my memory of this cake, I think it would be fine to use 1 cup buckwheat flour and 1 1/4 cups whole wheat or all-purpose flour. Buckwheat flour does tend to be on the drier side, as do the other gluten-free flours. So I can understand the cake not being as moist.
      I will need to try this recipe out a few different ways to let you know for certain, but a good place to start would be to up the amount of bananas or butter. You could certainly add an extra egg or two as well. But the bananas should definitely do the trick. Maybe use 1 1/2 cup mashed bananas and up the butter to 3/4 cup. The cake should turn out richer and more dense. You may need to change the baking time too. This is my best guess based on regularly making banana muffins (which, let’s be honest, are basically cupcakes) and tweaking here and there. Let me know how it goes. In the meantime, I’ll work on retesting this recipe and see what I can come up with. :)

Leave a Reply

Your email address will not be published.

Recipe rating