ASPARAGUS, SWISS CHARD, PEA AND TALEGGIO TART

320g all butter puff pastry sheet • 1 egg, beaten • 200g Swiss chard, stalks and leaves separated • 200g taleggio cheese, rind removed, sliced • 100g frozen peas • 400g asparagus, woody ends removed • ½ x 25g pack flat leaf parsley, leaves finely chopped • 2 garlic cloves, crushed • 5 tbsp extra virgin olive oil • 3 tbsp grated parmigiano reggiano