We grate the butter, the sugar, the semolina and the flour until they mix well. We add the eggs and the zest and we stir until the mixture is soft. We cover the mixture with a membrane and we place it in the refrigerator for 10 minutes. We preheat the oven to 190 degrees Celsius. We put a non-stick paper into 2 baking dishes and we make small balls that are placed 5 cm apart. We bake until the edges of the biscuits brown and the biscuits get a golden color. We let them cool down for 15 minutes. We serve them alone, after we have dived them in baking chocolate or as a accompaniment to our coffee or ice cream.