Black Magic Rum Cake Recipe

Prepare

Preheat the oven to 350°F (175°C). Grease and flour a 10-inch bundt pan thoroughly, then dust with cocoa powder to help the cake release. Alternatively, use nonstick spray with flour. Bring hot brewed coffee to a simmer and allow to cool slightly while assembling.

Dry ingredients

In a large bowl whisk together 2 cups all-purpose flour, 1 1/2 cups granulated sugar, 3/4 cup unsweetened dark cocoa powder, 1 1/2 tsp baking powder, 1 tsp baking soda, and 1/2 tsp fine sea salt until evenly combined and aerated.

Cream fats and eggs

In the bowl of a stand mixer fitted with the paddle (or using a large bowl and hand mixer), beat 1/2 cup softened unsalted butter and 1/2 cup vegetable oil together on medium speed until smooth. Add eggs one at a time (3 large eggs), mixing after each until incorporated. Scrape down the bowl.

Combine wet and dry

With mixer on low, add the dry ingredient mixture in three additions alternating with the buttermilk (1 cup) and hot coffee (1 cup) so you finish with dry ingredients. Begin and end with the dry mix. After the last addition, mix until just combined — do not overmix.

Add flavor

Stir in 2 tsp vanilla extract and 1/4 cup dark rum by hand until evenly distributed. The batter will be thin and dark; this is normal.

Bake

Pour the batter into the prepared bundt pan and smooth the top with a spatula. Bake in the preheated 350°F oven until a toothpick or skewer inserted into the center comes out with moist crumbs but not wet batter, about 45–55 minutes depending on oven. Rotate the pan once halfway through if your oven heats unevenly.

Cool slightly

Remove the cake from the oven and let it rest in the pan on a wire rack for 10–15 minutes. This brief rest helps the cake firm up so it unmolds cleanly.

Unmold

Run a thin knife around the inner edge of the bundt pan to loosen. Invert a rack or serving plate over the pan and carefully flip to release the cake. If it resists, let it cool 5 more minutes then try again.

Make glaze

While the cake is baking (or immediately after you remove it), prepare the warm glaze. In a medium saucepan over medium heat melt 1/2 cup unsalted butter with 1 cup packed light brown sugar, stirring until the sugar dissolves and the mixture is bubbly. Add 1 tbsp dark molasses and 1/4 tsp kosher salt and stir to combine.

Add rum and water

Carefully stir in 3/4 cup dark rum and 1/4 cup hot water (heat water separately to near-boil). Bring the mixture to a gentle simmer for 1–2 minutes to meld flavors, then remove from heat. Stir in 1 tsp vanilla extract. The glaze should be pourable but slightly syrupy.

Brush and soak

Place the unmolded cake on a wire rack set over a tray to catch drips. While the glaze is still warm, use a pastry brush or spoon to coat the top and sides of the cake with several tablespoons of glaze. Then, using a tablespoon, slowly spoon the rest of the warm glaze over the cake, allowing it to soak in. If you want more rum flavor, drizzle or brush the cake with the extra 2 tbsp dark rum designated for finishing.

Repeat if necessary

Allow 5–10 minutes for glaze to be absorbed, then repeat spooning any remaining glaze over the cake until it is evenly coated and the pan-drip tray collects excess. For a deeply soaked cake, you can poke the cake gently with a skewer before glazing to help the liquid penetrate.

Optional topping

If using, sprinkle 2 tbsp demerara or turbinado sugar evenly over the top so it adheres to the warm glaze for a crunchy finish. Dust lightly with 1 tbsp powdered sugar for contrast if desired.

Rest and serve

Let the glazed cake rest at room temperature for at least 1 hour so the glaze fully sets and the rum disperses through the crumb. Serve slices at room temperature. Store any leftover cake covered in the refrigerator up to 5 days (bring to room temperature before serving) — the flavor improves after a day as the rum continues to permeate the cake.