This one-bowl gluten-free buttermilk chocolate cake recipe is moist and tender with the secret ingredient, buttermilk, standing in for eggs. Frost it with a decadent and fluffy salted peanut butter buttercream!

Slices of buttermilk chocolate cake with peanut butter frosting on plates.

Easy Gluten Free Buttermilk Chocolate Cake Recipe

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. So a rich, dark chocolate cake topped with fluffy peanut butter frosting is my dream come true. For this recipe, I combined gluten-free oat and sweet white rice flour to create a slightly dense cake lightened up by a little buttermilk (and no eggs needed!). The frosting is a lovely mix of butter and peanut butter that's fluffed up with powdered sugar and balanced with a good amount of salt to bring out the flavor.

Why You'll Love This Buttermilk Chocolate Cake Recipe

There are so many variations of chocolate cake and I never get tired of making a new one. I love this cake for its flavor combination as well as the fact that you only need one bowl to throw it together. Here's why this is a winner of a buttermilk chocolate cake recipe:

A one-bowl cake. You should always have a one-bowl cake or two in your recipe arsenal and this is a gorgeously simple one. Just dump, whisk, stir, and bake!
Easy to make vegan. No eggs are called for in this cake, so it's super easy to adapt to being vegan/dairy-free if needed. I've outlined how to do it below.
Naturally gluten-free. The two gluten-free flours, oat and sweet rice flour, perform beautifully in this cake and you won't miss the all-purpose flour! The rest of the ingredients are already gluten-free.

Ingredients Needed

Cake

Oat flour - Whole grain, naturally gluten-free oat flour works wonderfully in baking
Sweet white rice flour - A starchy gluten-free flour, sweet white rice gives structure and binding to the cake
Granulated sugar
Cocoa powder - Use unsweetened cocoa powder
Baking soda
Salt - I always use fine grain sea salt in my recipes
Buttermilk - See my dairy-free substitution below
Coconut oil - Melted, or use olive oil
Vanilla extract - Pure vanilla extract will give the best flavor

Frosting

Butter - Use unsalted butter so you can easily adjust how much salt you want to taste in the frosting
Peanut butter - I use freshly ground peanut butter from my grocery store. You can use natural peanut butter, but make sure that the oil is fully incorporated before adding it to the frosting.
Powdered sugar - You can use more or less powdered sugar to taste
Salt - Add as much or as little salt as you prefer. I like this peanut butter frosting SALTED!

How to Make Buttermilk Chocolate Cake

Make Cake

Prepare: Grease and line a cake pan with parchment.
Make the batter: Whisk together the oat flour, sweet white rice flour, sugar, cocoa powder, baking soda, and salt. Add the buttermilk, coconut oil, and vanilla extract.
Bake: Pour batter into the pan, let it rest while the oven heats, then bake for 30-40 minutes. Cool the cake completely before frosting it.

Make Frosting

Make frosting: Cream the peanut butter and butter together, then add the sugar and salt to taste.

Two slices of gluten-free buttermilk chocolate cake on a white background with two forks.

Tips & Substitution Suggestions

A one-bowl cake is a thing of beauty! Check out my baking tips plus some substitution options below:

Rest the batter: Gluten-free batters always benefit from a slight rest so that the flour mix can fully hydrate before entering the oven. Let the batter rest in the pan while the oven preheats.
Use room temperature ingredients: Allowing your ingredients to rest on the counter for 15 minutes or so will help them incorporate better into the batter, resulting in a smoother crumb.
Oat flour substitute: Use sorghum flour or teff flour.
Sweet white rice flour substitute: Substitute an equal amount of tapioca starch.
Make the cake dairy-free: Mix one cup of your favorite non-dairy milk coconut with 1 tablespoon of vinegar, let stand for 15 minutes, and use in place of the buttermilk.
Go refined sugar-free: Swap the sugar for coconut sugar.
Try a different frosting: I adore this salted peanut butter frosting, but you should feel free to use this cake recipe as a jumping-off point for all sorts of cake iterations, including simply dusting it with powdered sugar and calling it a day.

Storage Suggestions

Place the cake in an airtight container or cover it tightly with foil and store it in the fridge for up to 5 days. Bring the cake to room temperature on the counter before serving it for the best results.

Gluten Free Buttermilk Chocolate Cake with Salted Peanut Butter Frosting