Coffee Mousse Cake Recipe

Preheat your oven to 350°F. Butter a 9-inch cake pan.

In a bowl, sift together the flour, baking powder, and salt, then whisk them to combine. In a separate bowl, cream the butter and 3/4 cup of sugar until light and fluffy, using a mixer or a heavy wooden spoon.

Whisk in the flour mixture, about 1/2 cup at a time, being careful not to overmix.

In a separate clean bowl, beat the egg whites with cream of tartar for about 2 minutes until soft peaks form. Gradually add the remaining 3 tablespoons of sugar and continue beating until you have medium, firm peaks.

Let the cake cool in the pan for 5 minutes, then carefully invert it onto a wire rack to cool completely. Make sure it's at room temperature before the next step.

Once cool, insert 4 toothpicks evenly around the sides of the cake to mark the halfway point. Using a long bread knife, carefully slice the cake into two even halves horizontally, following your toothpick guides.

Add the instant coffee to 2 tablespoons of warm water and stir until it's fully dissolved.

In a food processor or blender, process the cottage cheese until it's completely smooth and creamy, with no lumps remaining.

In a clean bowl, whisk 4 egg whites with cream of tartar until soft peaks form.

Gradually add the remaining 1/4 cup of sugar and continue beating until the peaks are medium and firm. Gently fold these whipped egg whites into the cottage cheese mixture until just combined, keeping the mousse light and airy.

Carefully place the second cake layer on top of the mousse. Spread the remaining mousse over the top and along the sides of the cake. An offset spatula can be helpful here for a smooth finish.

Transfer the cake to the fridge and chill for about 3 hours, or until the mousse is fully set.

Let the ganache cool for about 5 minutes, until it's only slightly warm to the touch. It should still be pourable but not hot enough to melt the mousse.

Pour the ganache evenly over the chilled cake, letting it drip down the sides. Return the cake to the fridge to chill for another 3 hours, allowing the ganache to set completely.