Start by making the sponge cake. In a stand mixer, beat the eggs with the sugar and orange zest until the mixture is light and fluffy. Gradually add the rice flour, folding it in gently with a wooden spoon or spatula, moving from the bottom up to keep the batter airy.

Pour the batter into a 9-inch (22 cm) round cake pan lined with parchment paper. Bake in a preheated oven at 400°F (200°C) for 10 minutes.

Remove from the oven and let cool.

Next, prepare the shortcrust pastry. On a work surface, place the rice flour and make a well in the center. Add the sugar, grated orange zest, vanilla sugar or extract, and the cold butter pieces.

Work the butter and sugar together until creamy, then add the eggs. Continue mixing, then add the pinch of salt and the baking powder. Gradually incorporate the flour and knead until the dough comes together. Shape into a ball, wrap in plastic wrap, and freeze for 30 minutes.

Meanwhile, blend the ricotta with the sugar and orange zest in a food processor until smooth and creamy. Stir in the dark chocolate shavings with a spatula and refrigerate.

After 30 minutes, remove the pastry from the freezer and divide it into two portions, one larger than the other.

Roll out the larger portion and press it into a 8-inch (20 cm) round cake pan, making a crust about 3/16 inch (4-5 mm) thick and forming a border about 1 1/4 inches (3 cm) high. Prick the pastry with a fork and freeze for 15 minutes.

Prepare the syrup. In a small saucepan, combine the orange juice, sugar, and a little water. Heat until the sugar is fully dissolved.

After 15 minutes, take the pan with the pastry from the freezer.

Cut the sponge cake into 1/2-inch (1 cm) wide strips and arrange them over the pastry crust.

Prick the sponge cake with a fork and soak it with the orange syrup.

Spread the ricotta filling evenly over the sponge cake, then cover with the remaining pastry.

Roll out the second portion of pastry into a disk about 3/16 inch (4-5 mm) thick and place it on top to seal the cake.

Bake at 350°F (180°C) for 40 minutes, or until the pastry is golden brown. Remove from the oven and let cool completely.

Meanwhile, prepare the glaze. In a bowl, combine the egg white, sugar, and orange juice. Beat with a mixer until the mixture is thick and glossy.

Once the cake is completely cool, transfer it to a serving platter and cover with the glaze.

Decorate the cake as you like. For example, slice oranges into 1/2-inch (1 cm) rounds, melt two tablespoons of sugar with a little water in a nonstick pan, and caramelize the orange slices. Let them cool on parchment paper, then arrange on the cake.

Store the cake in the refrigerator.