Preheat oven to 350 degrees Fahrenheit.

In a bowl, combine ground almonds, potato starch, baking powder, and salt.

In a separate bowl, mix egg yolks with oil and orange juice.

With a whisk or spatula, mix the contents of the two bowls together until completely combined in a smooth batter.

In the bowl of a mixer, beat egg whites with granulated sugar and vanilla sugar until they make a stable foam.

Gently fold the foam into the batter.

Divide batter between two loaf pans and bake about 45 to 55 minutes. Insert a toothpick in the center after 45 minutes; if it comes out dry, the cakes are ready.

Allow cakes to cool. To decorate as seen in the photo, spread some chilled lemon cream (from the Meringue Domes with Lemon Cream recipe) over the cakes. If you like, top with small meringue kisses.