Preheat the oven to 180ºC and prepare a tray. Place the egg whites in a bowl and beat them lightly until they foam, add the sugar and beat well with a wire mixer. until you have a thick mixture. Add the flour, almonds, hazelnuts, lemon, salt and spices.
Mix until you get a homogeneous, moist but malleable dough. With a teaspoon, take small portions and form balls with slightly moistened hands. Distribute them on the tray and bake for about 8-10 minutes, until very lightly browned. Let cool on a rack.
Melt the chopped chocolate in a bain-marie. Dip each cookie halfway, letting excess chocolate drain, and allow to dry completely before storing in an airtight container.