How to cook
Mix the sugar with the melted lard, egg, yolks, vanilla and flour. Knead a soft dough. Leave in the fridge for 1 hour.
Shape balls the size of a small walnut. First roll them in the beaten whites with a pinch of salt, then in the ground walnuts.
Arrange them in a tray and bake at 356°F (180 °C) for 20 min. Leave them to cool and stick them together in pairs with Nutella or marmalade.