Cream butter, sugar and vanilla sugar with the whisks of the mixer. Stir in the eggs one by one. Mix baking powder and flour and stir in portions briefly. Stir in ricotta.
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Line two baking trays with baking paper. Use a teaspoon to spread approx. 16 small blobs per tray, press down lightly, making sure there is a space between the blobs as the dough runs.
Bake in a hot oven for 10-12 minutes one after the other. Remove from the oven, rest on the baking tray for about 5 minutes, then let it cool down on a grid. Bake the rest of the dough in the same way.
For the icing, stir icing sugar with lemon peel, lemon juice and milk until smooth. Brush 5 Americans at a time with it, sprinkle with sugar pearls and let it dry. Do not decorate all the Americans at once, as the icing dries quickly and the beads will not stick to it.