Add the butter and ricotta to a bowl and mix with a wooden spoon until combined. Add the sifted flour, baking powder and a pinch of salt. Tip out onto a bench and knead together with your hands until the mixture comes together into a soft ball of pastry. (If not wanting to do it by hand, I have made this recipe in my Kitchenaid with a dough hook attached, it works out perfectly)Form into a ball, cover with plastic wrap and refrigerate for 30 minutes. Make the filling below while you wait.
Pre-heat oven to 180 C/350 F. Roll out pastry with a rolling pin on a lightly floured surface, to a thickness of about 3mm, and cut into 10cm (4inch) squares.
Put a heaped teaspoon of filling in the middle of each square and a couple of piece of the torn bocconcini. Pinch the opposite ends together with a little water.
Line an oven tray with baking paper and bake for about 25 minutes, or until golden brown. Serve warm