Small cakes:
Preheat the oven to 325°F (160°C).
In the mixing bowl, whisk the eggs with the sugar.
Add the flour and baking powder, previously sifted, and mix well.
Add the melted butter and limoncello and mix well.
Gently incorporate the blueberries with a spatula, being careful not to crush them.

Pour the mixture into 12 silicone molds (or other molds, but greased in this case).
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Remove from the molds and let cool on a rack.

Lemon sauce:
Pour all the ingredients into a small saucepan and bring to a boil, stirring constantly until thickened.
Let cool to room temperature before refrigerating.

Serve the small cakes topped with lemon sauce, accompanied by red fruits.