Preheat your oven to 350°F (175°C) and grease a 10-inch Bundt pan with nonstick cooking spray or butter.

In a large mixing bowl, beat the softened butter and granulated sugar together until light and fluffy (about 3-5 minutes).

One by one, add the eggs, mixing well after each addition.

In another bowl, whisk together the flour, baking powder, and instant espresso powder.

Gradually add the dry mixture to the creamed butter and eggs, alternating with sour cream. Start and end with the flour mixture.

Stir in the vanilla extract until well combined.

Pour the batter into the greased Bundt pan and smooth out the top.

Bake for 60-70 minutes, or until a toothpick inserted into the center comes out clean.

While the cake is baking, mix the cooled brewed coffee, coffee liqueur, and sugar in a bowl until the sugar dissolves.

Once the cake is done baking, allow it to cool in the pan for about 15 minutes.

Invert it onto a wire rack and poke holes across the top with a skewer. Pour the coffee soaking syrup over it.

In a separate bowl, whip the heavy cream until soft peaks form, then fold in the mascarpone cheese and powdered sugar.

Slice the cake, top with the mascarpone whipped topping, and dust with cocoa powder.