Ingredients
Equipment
Method
Bake the cake
- Preheat the oven to 350F, then grease two 9-inch round pans. Make sure the pans are fully coated so the layers release cleanly.
- Beat the butter and sugar until light and smooth. Add the eggs, sweet potato puree, buttermilk, and vanilla and beat until evenly combined.
- Fold the flour, cocoa powder, baking powder, baking soda, cinnamon, and salt into the batter until no dry streaks remain. Keep mixing gentle to preserve a tender crumb.
- Divide the batter evenly between the two prepared pans. Tap the pans lightly to level the tops.
- Bake for 35-40 minutes at 350F, until a toothpick in the center comes out with moist crumbs. Let the cakes cool completely before frosting.
Make ganache and frost
- Heat the heavy cream until steaming, then pour it over the dark chocolate chips and butter. Let it rest 2 minutes before stirring.
- Stir until smooth, then cool the ganache until spreadable. You want a thick, glossy texture that will spread without running.
- Beat the cooled ganache with powdered sugar and vanilla until fluffy. Scrape the sides as needed so the frosting becomes uniform.
- Frost between the layers and then frost all over the cake. Smooth the surface for a clean finish, letting excess drip slightly for coverage.
Notes
Pro tip: For best texture, use fully cooled cake layers—warm layers can melt the frosting. Store the frosted cake covered in the refrigerator for up to 4 days; freeze unfrosted layers (wrap well) for up to 2 months. For a lighter option, swap half the butter in the cake with neutral oil and expect a slightly softer crumb (ganache remains the same).