This recipe makes a small rectangular layer cake made from a single cake cut into thirds.
For the gluten-free génoise cake
¼ cup agave syrup
5 eggs, yolks and whites separated
½ teaspoon vanilla extract
2/3 cup millet flour (or all-purpose flour)
For the filling
8 ounces mascarpone
Grated zest of 1 lemon, plus some extra for garnish
2 tablespoons lemon juice
2 tablespoons agave syrup
For the syrup
4 tablespoons agave syrup
Juice of ½ lemon
1/3 cup water
Preheat the oven to 350 degrees Fahrenheit. Line a 8×9 pan or cookie sheet with parchment paper.
Beat the agave syrup with the egg yolks and vanilla extract in a medium mixing bowl until frothy. Gently whisk in the flour. Beat the egg whites to soft peaks and fold them into the egg yolk, agave and flour mixture. Transfer to the prepared pan and bake for 13 to 15 minutes.
Meanwhile, whisk the mascarpone, grated lemon zest, lemon juice and agave together in a medium bowl. Set aside.
When the cake is cooked, unmold it onto a large cutting board or dry surface, gently peel off the parchment paper and cut the cake into three rectangles of the same size. Let it cool.
Make the syrup by combining the agave syrup, lemon juice and water in a small saucepan. Cook the syrup over low heat for about 5 minutes.
Brush the first cake rectangle lightly with the syrup, spread a third of the mascarpone on the cake. Top it with the second cake rectangle, brush it with syrup and spread it with mascarpone. Repeat with the remaining cake rectangle and top it with a thin layer of mascarpone. Garnish with lemon zest, if you wish.