Preheat oven to 400° F / 205° C. Line a half-sheet rimmed baking tray with parchment.

In a medium bowl, combine strawberries, granulated sugar, cornstarch, and lemon juice. Set aside and allow the berries to macerate for 15 minutes, or until soft and juicy.

On a silicone rolling mat or lightly floured countertop, unroll the shortcrust pastry and use a rolling pin to roll it into a rectangle, approximately 10 x 14 inches in size. With a 6-inch pastry ring or round metal cutter, cut 2 discs. (If you don’t have a pastry ring, you can trace around a dessert plate.) Re-roll scraps and cut 2 additional discs.

Arrange discs on prepared tray.

Spread strawberry jam in the middle of each disc, allowing a 1-inch border around the outside edge.

Spoon the fresh strawberry filling on top of the jam, dividing it equally amongst the discs. Discard any excess liquid in the bottom of the bowl.

Sprinkle with the basil.

Tightly fold the edges of the pastry inward to seal in the strawberries.

With a pastry brush, brush the pastry with a thin coat of egg wash.

Sprinkle generously with Demerara sugar.

Bake in preheated oven for 18-20 minutes, or until bubbly and golden brown.

Serve warm or at room temperature.