Thinly roll out the pasta until it is about 2.5mm (⅛in) thick. Cut out circles of dough, about 6cm (2½ in) in diameter, using a pastry cutter. Put about 1 teaspoon of filling on one half of each circle and moisten the edges of the dough with a little water.
Fold each dough circle in half over the filling and press the edges together firmly to seal. Carefully curve the half-moon shape round y our forefinger, turning up the sealed edges like a hat brim. Pinch the pointed ends together. Repeat with the rest of the circles of dough. Cook the tortellini in the same way as ravioli (above).