Rich Mocha Cake With Walnut Crunch Frosting to Finishing Tips

Written by jheelum basu | October 14, 2025

Being a distant relative of the American coffee cake, which, according to the experts, is mostly of either German or Dutch origin, with yeasted breads spiked with nuts, dried fruit, spices and topped with crumb, the British version of the rich chocolate mocha cake represents an actual slice of layered, coffee-flavoured cake with a crunchy walnut twist.

Here’s a look at how the delectable rich chocolate mocha cake with walnut crunch is made from scratch.

Ingredients

• Unsalted, softened butter- ½ cup
• Self-raising flour- 1 cup
• Baking powder- 1 teaspoon
• Granulated sugar- 1.5 cups
• Light brown sugar- 1.5 cups
• Eggs- 4
• Crushed walnuts- ½ cup
• Instant coffee- 2 tablespoons
• Coffee essence- 2 tablespoons
• Boiling water- 1 tablespoon

Coffee Buttercream Frosting

• Coffee essence- 2 tablespoons
• Unsalted butter at room temperature- 2 cups
• Icing Sugar- 3.5 cups

Topping

• Extra walnuts for decoration
• Cocoa powder for dusting

How to bake the cake: Step-by-step guide

Initial prep

1. Oven to be pre-heated to 180°C (160°C for fan ovens) or 350°F.
2. An 8-inch square cake tin to be used for baking the cake
3. The sides of the tin should be greased, while the base of the tin should be lined with parchment paper.
4. Walnuts to be dry-roasted in a pan over medium heat. The nuts should be cooled after that.
5. The cooled walnut pieces should be placed in a food processor and pulsed until they reach a coarse, nutty powder.

The cake batter

1. The batter preparation starts with adding the softened butter, granulated sugar, and light brown sugar to a mixing bowl. All of the ingredients are then beaten together until the mixture reaches a creamy texture.
2. Four eggs are added one at a time. The eggs are whisked well after each addition.
3. In a separate bowl, the instant coffee powder is dissolved in boiling water.
4. The mixture is allowed to cool completely. The cooled instant coffee and the coffee essence are mixed before it is added to the batter.
5. The self-raising flour and the baking powder are then added to the batter.
6. In the end, the crushed walnuts are mixed as well until evenly distributed.

Baking the cake

1. The batter is poured into the greased cake tin and is baked in the preheated oven for about 45 minutes, or until the sponge has risen.
2. Once the cake is baked, it is allowed to cool in the tin for approximately 10 minutes before it is taken out of the tin.

Buttercream: The tastemaker

1. In a mixing bowl, the softened butter and icing sugar are combined and beaten on low to medium speed until the mixture attains a creamy and smooth texture.
2. The next step is the addition of the coffee essence and whisking it until fully incorporated.

Frosting and garnishing: The final steps

1. The cooled sponge cake is placed upside down on a cake stand or serving plate, and a generous amount of the buttercream is spread across the top layer.
2. The edges are smoothed out with a spatula.
3. The top layer is then dusted with sprinkles of cocoa powder.
4. The remaining walnuts are used for garnishing the cake.

A few tips & tricks to enhance the taste

To further enhance the taste of the rich chocolate mocha cake with walnut crunch, chocolate chips can be added to the batter.

To infuse a stronger flavor, several other types of nuts, such as pecans or hazelnuts, can be added.

Instead of coffee buttercream, a chocolate buttercream or a simple vanilla frosting can be considered as well for a different flavor profile.

For garnishing, fresh berries can be used as well to add a pop of color and a refreshing contrast to the cake's flavors.