Preheat the oven to 180°F.

Chop the almonds in a blender.

Crack the eggs and transfer the yolks into the bowl of a stand-mixer. Transfer the whites to a different bowl.

Add sugar to the stand-mixer bowl. Mix until the eggs and sugar are fully incorporated.

Add the butter, lemon zest, and flour. Mix the batter and add the chopped almonds.

In the other bowl, beat the egg whites until stiff and add to the batter little by little. Keep mixing.

Grease a cake pan and pour in the batter.

Decorate the top of the mixture with whole almonds and bake for about 45 minutes.

Remove from the oven and let cool.

Sprinkle a thin layer of powdered sugar on top. Serve with a scoop of vanilla ice cream or whipped cream and grated lemon zest.