Thaw the wonton pastry sheets. Cut out the strawberry stalks and halve the strawberries. Beat the egg and whisk. Place half a strawberry on each sheet of dough, sprinkle with brown sugar (1 pinch), brush the edges with the beaten egg, join the corners of the pastry over the filling (makes 30 pieces!), Place on a baking sheet lined with baking paper and cover with the remaining egg coat. Preheat the oven to 180 ° C, place the tray on the middle rack and bake for about 10 minutes until golden brown. Take out, arrange on a platter and dust with powdered sugar.