Gluten Free Chocolate Coffee Walnut Layer Cake

Walnuts are the ones that are always left out. They don’t have a whole pie dedicated to them at Thanksgiving, they don’t supply millions of school children (and children at heart) with America’s favorite sandwich, they don’t even make milk (apparently even cashews do now!)! But they are one of my favorite nuts. Arguably the most delicate nut, buttery, with a light crunch and a hint of bitterness that rounds out any treat. I used to add them to my morning bowl of yogurt and berries every day, and still have a strong affinity for their papery skins and carefully-folded contours. So, when we visited friends in Paso Robles a weekend ago, and got to stop at a farm stand selling heaps of fresh, raw, heirloom (!!) walnuts, I knew a new walnut recipe was about to be created. If you’re in the area, check out Manzanita Manor Organics farm – they have incredible walnuts (raw, roasted, covered in dark chocolate…), and other delicacies like walnut oil, walnut flour, and walnut butter!

After the trip, I spent days ruminating over what type of walnut-based recipe I wanted to create. Walnuts are often added as a toss-in to carrot cakes or other fruit + nut fall breads but honestly those never do them justice. I wanted to create something that celebrated the walnut, that elevated it to the refined, sophistication of pistachio or macadamia. So, this tower of walnut elegance was born. Layers of dense, rich, buttery coffee + walnut cakes (with walnut flour and chopped toasted walnuts, in addition to coffee), separated by the silkiest coffee buttercream, a layer of more toasted walnuts, and a drizzle of chocolate ganache, and topped with more of all of the above. The cake layers themselves came out of the oven smelling almost mapley, which I love (who knew! coffee + walnut is a gem pairing), and the whole package is a Monday morning dream (I may go have a slice right now).

So, I highly recommend making this – especially because the election is tomorrow (GO VOOOOOOTE!!) and the stress eating is REAL. Or make it tomorrow for full on election coverage cake time. If you’re a coffee fan, check out our coffee chocolate swiss roll, or these coffee + chocolate cupcakes. If you’re into nuts, check out these pecan pie bars, or these toasted pecan shortbread cookies!

Print Recipe

Gluten Free Chocolate Coffee Walnut Layer Cake

This decadent layer cake is the definition of indulgence: rich, buttery coffee and walnut cake layers, with coffee buttercream, more toasted walnuts, and dark chocolate ganache!

Prep Time3 hours hrs

Cook Time35 minutes mins

Chilling time3 hours hrs

Course: Dessert

Cuisine: American

Diet: Gluten Free

Keyword: birthday cake, buttercream, cake, chocolate coffee, coffee, ganache, gluten free, layer cake, rich, toasted walnuts, walnut

Servings: 10 people

Calories: 500kcal

Author: Amelia Farber

Equipment

• Four 6-inch round cake pans (or two 9-inch round pans for a two-layer cake)
• Electric mixer
• Piping bag and tips
• Cake scraper

Ingredients

For the cake layers:

• 3 large eggs
• 3/4 Cup sour cream
• 3/4 Cup canola oil
• 1 tsp vanilla extract
• 2 Tbsp walnut oil
• 1 Cup white sugar
• 1/2 Cup milk
• 2 tsp instant coffee
• 1 1/2 Cup gluten free 1-1 flour mix with xanthan gum added (if it doesn't have xanthan gum, add 1 teaspoon xanthan gum)
• 1/2 Cup blanched almond flour
• 1/2 Cup packed, finely ground raw walnuts
• 2 tsp baking powder
• 1/2 tsp salt
• 1 1/2 Cups chopped toasted walnuts instructions below

For the coffee buttercream:

• 2 Cups salted butter room temperature
• 2-3 Cups sifted powdered sugar
• 3 Tbsp heavy cream
• 3 Tbsp instant coffee
• 1/2 tsp vanilla extract

For the ganache:

• 1 Cup heavy cream
• 10 oz semi sweet chocolate chips
• 1 tsp instant coffee

For construction:

• 3/4 Cup chopped toasted walnuts instructions below

Instructions

To make the cake layers:

• First, preheat the oven to 350° Fahrenheit and grease four 6-inch round cake pans (or two 9-inch round cake pans if you're making a two-layer cake) with butter or cooking spray, then set aside. Then, toast your walnuts! Toast enough for the cake and for the construction (about 2 1/2 cups). Pour walnuts into a large frying pan and heat over medium heat for 5-8 minutes, stirring frequently, until lightly browned but not burnt. Remove from pan and let cool on a cutting board. Once cool, chop and set aside.
• Then make your cakes! In a large bowl, whisk together the eggs, sour cream, oil, vanilla, walnut oil, and sugar until smooth and combined. Separately, in a small bowl or measuring cup, mix the instant coffee with the milk until completely dissolved, then add the coffee milk to your cake batter and mix to combine. Using a food processor or nutribullet, blitz up raw walnuts to make your finely ground walnut flour, then add the walnut flour, almond flour, and gluten free 1-1 flour to your batter and whisk to combine. Finally, add in the baking powder, salt, and chopped toasted walnuts and mix. Pour your cake batter into your prepared pans and bake for 30-35 minutes or until a skewer inserted into the center of one of the cakes comes out clean. Let cakes cool completely before turning out.
• Once cakes are cool, remove from pans, wrap in plastic wrap, and freeze for 30 minutes.

To make the buttercream:

• While your cakes are freezing, make the buttercream. In a large bowl, using an electric mixer, beat the room temp butter with 1 cup of sifted powdered sugar until smooth. Add the vanilla and a second cup of powdered sugar and beat to combine. Then, in a small bowl, mix the cream and instant coffee until completely dissolved and then add the coffee cream into your bowl and beat until smooth. Add more powdered sugar if the frosting is too stiff. Scoop buttercream into a large pastry bag and cut off a 1/2 inch opening at the tip.

To make the ganache:

• In a heat-proof bowl, heat the cream in the microwave for 45 seconds to a minute until steaming and frothy. Pour in your chocolate chips and let stand for 2-3 minutes before stirring. Stir until ganache is silky and smooth, then let the ganache cool in the fridge for 10-15 minutes until it's room temperature or cooler. Once cool, pour ganache into a large piping bag (do not cut off the tip yet).

To construct the cake:

• Place one of the frozen cake layers on a cake board on a cake stand/rotating cake stand. Pipe coffee buttercream onto the layer, spread until smooth, then add a layer of toasted walnuts and a light drizzle of ganache (cut off a small opening at the tip of the piping bag). Repeat this step until the last cake layer is on top, then frost the entire outside and top of the cake to crumb coat. Freeze cake for 20 minutes until crumb coat has set, then apply the outer coating of frosting using your cake scraper. Press toasted walnuts into the buttercream around the base of the cake, then carefully drizzle ganache on top of the cake so that it drips down the sides. Freeze again for 30 minutes or until ganache is set. Remove and pipe remaining buttercream on the top of the cake, and add toasted walnuts, then freeze again for 30 minutes or for hours. Remove from freezer two hours before serving.

Tag @sisterssansgluten on Instagram if you snap a photo of your cake!

Food photography and styling by Amelia Farber