{Gluten-Free} Buttermilk Chocolate Cake with Salted Peanut Butter Frosting
It’s no secret that I love peanut butter and chocolate together. Give me a bag of Justin’s milk chocolate peanut butter cups and I’ll happily call it a day. Pair a dark chocolate cake with a fluffy cap of salted peanut butter frosting and I’ll be set for the whole weekend. To that end, today’s recipe is an update of an old classic, an eggless chocolate cake made with buttermilk and just two gluten-free flours. I adapted it long ago from the Fannie Farmer cookbook and recently revisited it because it is such a classic: a tender crumb, quick to whip together, and now incorporates natural sweeteners.
You should always have a one-bowl cake or two in your recipe arsenal and this one, for a simple chocolate cake with or without frosting, fits the bill perfectly. Sometimes you just need a chocolate cake — because it’s your birthday, because it’s Saturday, because you need a slice of something sweet to go with your afternoon cuppa, because you have that bit of buttermilk in the fridge that needed to be used yesterday.
In this recipe I combined oat and sweet white rice flours and swapped out the granulated sugar in the original recipe for maple sugar. This is a slightly dense cake, as the buttermilk replaces eggs so it’s not as soft as some. The frosting is a lovely mix of butter and peanut butter sweetened with homemade coconut powdered sugar with a good amount of salt to balance and bring out the flavor. I recommend letting it come to room temperature before serving for the best-tasting crumb.
You could also serve this plain, with a little whipped cream or ice cream. This unassuming gem comes together in a snap; enjoy.
Til next time – N x
Need substitutions? Swap tapioca for the sweet rice flour and sorghum flour for the oat flour. starch. Try coconut sugar in place of the maple sugar or just use brown sugar. For the frosting, use regular powdered sugar for the powdered coconut sugar.
To make the cake dairy-free: mix one cup coconut milk with 1 tablespoon vinegar, let stand for 15 minutes, and use in place of the buttermilk.
Gluten-Free Buttermilk Chocolate Cake
Ingredients
For Cake
- 1 ¼ cups/140 g gluten-free oat flour
- ¾ cup/90 g sweet white rice flour
- 1 cup maple sugar or sugar
- ½ cup unsweetened cocoa powder
- 1 tsp baking soda
- ½ tsp fine grain sea salt
- 1 cup buttermilk
- ½ cup melted coconut oil
- 2 tsp pure vanilla extract
For Frosting
- ½ cup unsalted butter or 1/2 cup softened coconut oil, at room temperature
- ¼ ¼ cup freshly ground peanut butter
- ¼ cup homemade powdered sugar or powdered sugar
- ½ tsp fine grain sea salt, or to taste
Instructions
Make Cake
- Grease and and line with parchment paper one 8 or 9-inch round cake pan.
- In a large bowl, whisk together the flours, maple sugar, cocoa powder, baking soda, and salt. Add the buttermilk, coconut oil and vanilla extract and whisk together very well to combine.
- Pour batter evenly into the prepared pan and smooth top with a rubber spatula. Let rest while oven is heating. Preheat oven to 350° F.
- Place pan in the oven and bake about 30-40 minutes (mine took about 38 minutes), until a tester inserted into the middle of the cake comes out clean. Remove from oven and place on a rack to cool 5 minutes, then turn out onto the rack to cool completely.
Make Frosting
- In a large bowl, cream the peanut butter and butter together until light and fluffy. Add the sugar, and keep mixing until smooth and creamy. Add as much or as little salt as you like.
- Cake will keep in the fridge, covered, for 5 days.