Preheat the oven to 180°C, fan 160°C, gas 4. On a lightly floured surface, roll out the pastry to a thickness of 3mm, then cut out 12 rounds using a 7cm fluted cutter. Cut out 12 crowns from the remaining pastry using a sharp knife (an adults-only job).
Gently press the pastry rounds into a 12-hole cupcake tin and set aside. In a bowl, mix together the jam, strawberries and orange zest. Spoon into the pastry rounds, being careful not to overfill, and top each with a pastry crown.
Brush the crown tops with the beaten egg and bake in the oven for 15 minutes, until golden. Remove from the oven and cool slightly before serving.