(1) Using a sharp knife, cut the ends off the onion.Peel it,then cut it in into quarters. Slice each quarters finely.
(2) Put the sliced onion into a frying pan with the olive oil. Gently cook the onion on a low heat for 5 minutes.
(3) Take the pan off the heat and stir in the herbs, salt and pepper. Then , unroll the pastry and cut it into 24 squares.
(4) Put the squares onto the baking trays, leaving spaces between them. Prick the middle of each squares twice with a fork.
(5) Open the mozzarella bag and pour away any liquid . Cut the mozzarella into tiny cubes. Then, cut the tomatoes in half.
(6) Pour the milk into a mug . Then,brush milk around the edges of each square, making a border about 1 cm (1/2in) wide.
(7) Spoon some of the onion and herb mixture onto each pastry square. Make sure that you dont cover the milk border.
(8) Put half of a tomato onto each square, then scatter a few cubes of mozzarella on top of one.
(9) Cook the pastries for 12-15 mintues . Lift them off the baking trays with a spatula and leave them to cool for 5 minutes
Tips: the edges will rise and turn brown. Cool for 5 minutes befroe eating .