Preparation time: 20 minutes plus baking
½ teaspoon salt
½ teaspoon baking soda
1 ½ cups all purpose flour
6 tablespoon unsalted butter, room temperature
1 cup granulated sugar
1 teaspoon vanilla extract
4 large eggs
¼ cup buttermilk
3 tablespoons cocoa powder
½ teaspoon black walnut flavoring
Preheat oven to 350 degrees. Prepare a round cake pan by spraying with vegetable oil spray and dusting with flour.
Combine the salt, baking soda and flour in a small bowl. Set aside.
Use an electric mixer to combine the butter and sugar until light and fluffy. Stir in the vanilla and the eggs, adding one at a time. Add the flour mixture and buttermilk in 3 additions, alternating ½ flour mixture with ½ buttermilk until just blended. Spread half of the batter into the prepared cake pan.
Stir in the cocoa and black walnut flavoring into the remaining batter. Place the remaining batter onto the vanilla batter in large spoonfuls. With the tip of a knife, swirl the chocolate batter onto the vanilla batter being careful t not to over-mix.
Bake for 30 to 35 minutes or until toothpick inserted into the center comes out clean. Cool on a wire rack. Dust with confectioners’ sugar before serving.