For the cake:
- 1 cup unsalted butter, softened
- 1 1/2 cups sugar
- 3 eggs
- 2 teaspoons vanilla extract
- 3 cups sifted unbleached flour (sift before measuring)
- 1 1/2 teaspoons baking soda
- 1 1/2 teaspoons baking powder
- 3/4 teaspoons fine sea salt
- 1 cup sour cream
- 1/2 cup light brown sugar
- 1/2 cup chopped walnuts or pecans
- 2 teaspoons cinnamon
- 3/4 cup chocolate chips or chopped dark chocolate
For the cake:
Step 1: Preheat the oven to 350F. Grease and flour a 10-inch tube pan.
Step 2: Beat together 1 cup softened butter and 1 1/2 cups sugar in the bowl of a stand mixer with the paddle attachment until creamy.
Step 3: Add the 3 eggs one at a time, beating well after each addition.
Step 4: Beat in 2 teaspoons vanilla.
Step 5: In a separate bowl, mix together 3 cups flour, 1 1/2 teaspoons baking soda, 1 1/2 teaspoons baking soda and 3/4 teaspoon salt.
Step 6: Using a rubber spatula, add the flour mixture in three parts to the butter mixture alternating with the sour cream, starting and ending with the flour. Mix after each addition, but do not over mix or beat.
Step 7: To make the topping, mix 1/2 cup light brown sugar, 1/2 cup nuts, 2 teaspoons cinnamon and 3/4 cups chocolate chips together in a small bowl.
Step 8: To assemble, spread half the batter in the prepared tube pan, and sprinkle on half of the topping. Repeat with the rest of the batter and topping.
Step 9: Bake the cake for 45 to 50 minutes, or until a cake tester inserted into the center comes out clean.
Step 10: Remove the cake from the oven; let cool on a wire rack for 30 minutes. Carefully remove the cake and turn right-side up (topping up) on a platter to serve.
Step 11: Serve the cake at room temperature, or wrap the completely cooled cake airtight, and store at room temperature for several days; freeze for longer storage.