This easy, one-layer walnut cake is moist, nutty, and lightly spiced. Topped with a creamy coffee or vanilla frosting, it’s a timeless dessert perfect for any gathering.
Sometimes the simplest desserts are the most memorable. This Walnut Cake is a testament to that—a humble, single-layer cake where toasted walnuts are the undisputed star. The cake itself is incredibly moist and tender, with a subtle warmth from cinnamon and a rich, nutty flavor in every bite.
Topped with a complementary coffee or vanilla frosting, it strikes the perfect balance between homey comfort and elegant simplicity. It’s the kind of cake that doesn’t need a special occasion but makes any afternoon feel a little more special.
The Science of a Moist, Nut-Forward Crumb
This cake achieves its moist, dense-yet-tender texture through a combination of oil-based hydration and the unique properties of toasted walnuts. Using vegetable oil instead of butter coats the flour proteins more thoroughly, inhibiting gluten formation and locking in moisture for a softer crumb that stays fresh for days.
The toasted walnuts do more than add flavor; when finely ground, they release their natural oils, which further enriches the batter and contributes to the cake’s moistness. The toasting process is crucial—it deepens their flavor via the Maillard reaction, transforming them from bland and bitter to rich and aromatic.
The small amount of cinnamon enhances the nutty flavor without overpowering it. The frosting, whether coffee or vanilla, uses confectioners’ sugar for a smooth texture that beautifully complements the cake’s rustic texture without being overly sweet.
Ingredients
For the Walnut Cake:
- 1 ½ cups (150g) walnuts, toasted and cooled*
- 1 ½ cups (188g) all-purpose flour
- 2 teaspoons baking powder
- ½ teaspoon baking soda
- ½ teaspoon salt
- ½ teaspoon ground cinnamon
- ¾ cup (150g) granulated sugar
- ½ cup (120ml) vegetable or canola oil
- 2 large eggs, room temperature
- 1 teaspoon vanilla extract
- ⅔ cup (160ml) buttermilk, room temperature
For the Coffee Frosting (or Vanilla):
- ½ cup (1 stick / 113g) unsalted butter, softened
- 2 cups (240g) confectioners’ sugar, sifted
- 2-3 teaspoons strong brewed coffee, cooled (or milk for vanilla)
- 1 teaspoon vanilla extract
- Pinch of salt
- Extra walnut halves for garnish
*Toast walnuts at 350°F for 8-10 minutes until fragrant. Let cool completely before using.
Instructions
1. Prep: Preheat oven to 350°F (175°C). Grease and flour a 9-inch round cake pan, or line with parchment paper. Toast walnuts, let cool, then finely chop or pulse in a food processor until they resemble coarse meal (some larger pieces are fine).
2. Mix Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon. Stir in the processed walnuts.
3. Mix Wet Ingredients: In a large bowl, whisk together the sugar and oil until combined. Whisk in the eggs one at a time, then the vanilla.
4. Combine: Add about one-third of the dry ingredients to the wet, mixing just until combined. Stir in half of the buttermilk. Repeat with another third of the dry, the remaining buttermilk, and finally the last of the dry ingredients. Mix until just combined—do not overmix.
5. Bake: Pour batter into prepared pan and smooth the top. Bake for 30-35 minutes, until a toothpick inserted in the center comes out clean.
6. Cool: Let cake cool in the pan for 10 minutes, then turn out onto a wire rack to cool completely.
7. Make Frosting: While cake cools, beat softened butter until smooth. Gradually add sifted confectioners’ sugar on low speed. Add vanilla, salt, and coffee (or milk) one teaspoon at a time until the frosting is creamy and spreadable. Beat on high for 1-2 minutes until fluffy.
8. Frost & Serve: Once cake is completely cool, spread frosting over the top. Garnish with a ring of toasted walnut halves. Slice and serve.
Pro-Tips for Cake Perfection
- Toast Your Nuts: This is non-negotiable for deep, rich flavor. Cool them completely before grinding to prevent releasing oils that can make the cake greasy.
- Buttermilk Magic: Its acidity tenderizes the gluten and reacts with the baking soda for a light, tender crumb. No buttermilk? Add 2 tsp lemon juice to ⅔ cup milk and let sit 5 minutes.
- Room Temperature Ingredients: Cold eggs or buttermilk can cause the oil to solidify and result in a dense cake.
- The Alternating Method: Adding the dry and wet ingredients in stages prevents overmixing and ensures a smooth, well-hydrated batter.
- Cool Completely Before Frosting: Any residual warmth will melt the butter-based frosting.
- Frosting Consistency: For a thick, pipeable frosting, use less liquid. For a smooth, spreadable glaze, add a touch more coffee or milk.
- Storage: Store covered at room temperature for up to 3 days. The flavors meld and improve overnight.
- Flavor Variations: Add ½ cup of raisins or chopped dates to the batter, or use maple syrup in place of some sugar for an autumnal twist.
This Classic Walnut Cake is a delicious celebration of simplicity and flavor.
