Preheat the oven to 350 degrees F. Butter a springform pan and line the bottom with parchment paper.

Use an electric mixer to cream the butter and 1/4 cup sugar until light and fluffy, about 3-4 minutes.

Separate 3 of the eggs. Beat 3 yolks into the sugar-butter mixture until it turns pale. Then add the almond extract.

In a food processor, grind the nuts into a fine meal. Add 3/4 cup granulated sugar, lemon zest and 3 whole eggs. Pulse to mix everything together.

Clean the beaters of the electric mixer. In a medium bowl, beat the egg whites. When they become foamy, slowly add the remaining sugar, beating until soft peaks form.

Gently stir the nut mixture into the creamed butter and sugar.

Fold in the egg whites.

Transfer the batter to the prepared pan and top with sliced almonds.

Bake until the cake is golden brown and a toothpick inserted in the center comes out clean, about 30 minutes. Let the cake cool for 10 minutes before removing from the pan. Cool on a wire rack.

Dust with confectioners’ sugar before serving.