Ingredients
- Chocolate Streusel
- 1 cup chopped walnuts
- 1 cup semisweet chocolate chips
- 1/2 cup (packed) light brown sugar
- 2 teaspoons ground cinnamon
- Pinch of kosher salt
- Cake and Assembly
- 1 cup (2 sticks) unsalted butter, room temperature, plus more for pan
- 4 cups all-purpose flour, plus more for pan
- 2 teaspoons baking powder
- 2 teaspoons baking soda
- 1/2 teaspoon kosher salt
- 2 cups granulated sugar
- 4 large eggs
- 2 cups sour cream
- 2 teaspoons vanilla extract
- Special Equipment
- A 12-cup Bundt pan
Preparation
Step 1
Cake and Assembly
Preheat oven to 350°. Butter and flour Bundt pan, tapping out excess flour. Whisk 4 cups flour, baking powder, baking soda, and salt in a medium bowl. Using an electric mixer on medium-high speed, beat granulated sugar and 1 cup butter in a large bowl until light and fluffy, about 5 minutes. Add eggs one at a time, beating to blend and scraping down sides of bowl after each addition. Reduce speed to low and add dry ingredients in 2 additions, alternating with sour cream. Add vanilla and beat just to combine.
Transfer half of batter to prepared pan; smooth surface. Sprinkle half of streusel evenly over batter. Scrape in remaining batter, smooth surface, and sprinkle with remaining streusel. Bake cake until golden brown and a tester inserted into the center comes out clean, 70–80 minutes. Transfer pan to a wire rack and let cake cool in pan 30 minutes before inverting onto wire rack. Let cool completely.
Do Ahead: Cake can be made 3 days ahead. Store tightly covered at room temperature.