Preheat your oven to 350°F (175°C). Grease a 9-inch cake pan and line with parchment paper.

In a large bowl, sift together 2 cups pastry flour, ¾ cup cocoa powder, 2 teaspoons baking powder, ¾ teaspoon baking soda, ½ teaspoon ground cloves, and ¾ teaspoon salt. Set aside.

In another bowl, whisk together 2 large eggs, ¾ cup dark brown sugar, ½ cup granulated sugar, ½ cup melted butter, ½ cup sunflower oil, ¾ cup buttermilk, 2 teaspoons espresso powder, and 2 teaspoons vanilla extract.

Gradually fold the dry ingredients into the wet mixture until smooth. Slowly add 1 cup spiced rum and mix until fully incorporated. The batter should be glossy and pourable.

Pour the batter into the prepared pan and smooth the top. Bake in preheated oven for 50–60 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool in the pan for 15 minutes.

In a saucepan over medium heat, combine 1 cup sugar, ½ cup butter, ¼ cup water, ¼ cup cocoa powder, and 1 teaspoon salt. Stir constantly until sugar dissolves and mixture comes to a gentle boil. Remove from heat and stir in ⅓ cup spiced rum and 1 teaspoon vanilla extract. Let cool slightly.

Place the cake on a cooling rack over a tray to catch drips. Pour the warm glaze evenly over the cake, allowing it to soak in and coat the sides.

Allow the cake to rest for 20–30 minutes so the glaze sets. Slice and serve at room temperature. Pairs beautifully with whipped cream or vanilla ice cream.