Preheat the oven to 425°F / 220°C. Line a large baking sheet with baking parchment.
Lay the thawed puff pastry sheet on the lined tray.
Place the berries into four separate bowls. Zest half a lemon into each and squeeze the juice of half a lemon into each.
Add 2 tablespoons of sugar and ½ teaspoon of cornstarch into each berry bowl. Mix gently.
Score a half an inch (1.25 cm) border around the pastry sheet being careful not to cut all the way through. Tip the bowls of fruit in separate rows onto the baking sheet then bake in the oven for around 20 minutes until puffed and golden
Allow to cool slightly then heat the strawberry jam and brush over the top of the berries to give them a beautiful glaze
Serve with freshly whipped cream—you’ve earned it!