In a mixing bowl, combine the mascarpone and sugar.

Add the eggs one at a time, mixing well after each addition.

Add the flour, baking powder, and lemon zest, then mix until the batter is smooth.

Pour the batter into a greased and parchment-lined 7-inch (18 cm) cake pan.

Preheat your oven to 350°F (180°C), then bake for about 40 minutes, depending on your oven.

Let the cake cool slightly before removing it from the pan.