• cooking spray with flour, such as Baker’s Joy®
• 3 cups all-purpose flour
• 2 1/2 teaspoons pumpkin pie spice
• 2 teaspoons baking powder
• 1 teaspoon baking soda
• 1 teaspoon salt
• 1/2 cup unsalted butter, softened
• 1/4 cup vegetable oil
• 2 cups white sugar
• 4 large eggs, at room temperature
• 1 (15-ounce can) pumpkin puree (not pumpkin pie filling)
• 2 teaspoons vanilla extract
• 1 cup sour cream, at room temperature

Black Cocoa Batter:

• 3 tablespoons black cocoa powder (such as The Cocoa Trader Black Dutched Cocoa Powder)
• 3 tablespoons unsweetened Dutch processed cocoa powder (such as Ghirardelli Premium 100% Unsweetened Baking Cocoa Powder)
• 2 tablespoons white sugar
• 1/4 cup milk
• 1 teaspoon espresso powder (optional)
• 1 (1 ounce) square semi-sweet baking chocolate, melted and cooled slightly

Black Cocoa Icing:

• 1 cup confectioner’s sugar
• 2 tablespoons black cocoa powder
• 1 teaspoon vanilla extract
• 1 pinch salt
• 6 tablespoons heavy cream, or as needed

Preheat the oven to 350 degrees F. Spray a 12-cup Bundt pan with a baking spray containing flour, such as Baker’s Joy®. In a large bowl, sift together flour, pumpkin pie spice, baking powder, baking soda, and salt. In another large bowl, beat butter, oil, and 2 cups white sugar on medium-high speed with an electric mixer until creamy, about 3 minutes. Add in eggs, 1 at a time, beating well after each addition. After adding in the last egg, beat mixture on medium-high speed until doubled in volume, about 5 minutes. Add in pumpkin and vanilla, and mix until incorporated. Reduce mixer speed to low; pour in half of dry ingredients, and mix until just combined. Add in sour cream; mix until just combined. Add in remaining dry ingredients and mix until just combined.

Measure out 3 cups batter into another bowl. To this 3 cups batter, add 3 tablespoon black cocoa powder, unsweetened cocoa powder, 2 tablespoons sugar, milk, espresso powder, and melted semi-sweet chocolate. Mix on low speed until combined. Place 1/3 of black cocoa batter into an even layer in the bottom of the prepared Bundt pan. Pour 1/2 of plain pumpkin batter over the black cocoa layer. Add another 1/3 of black cocoa batter over the top of plain pumpkin batter. Layer remaining 1/2 of plain pumpkin batter over that. Finish with remaining 1/3 of the black cocoa batter. Bake cake in the preheated oven until a bamboo skewer inserted into the center of the cake comes out mostly clean, 60 to 65 minutes. Allow cake to cool in pan 25 to 30 minutes before inverting onto a wire rack to cool completely. To make icing, place powdered sugar, 2 tablespoons black cocoa, 1 teaspoon vanilla extract, pinch of salt, and heavy cream into a bowl. Whisk until smooth. Drizzle icing over cooled cake.