In a non-stick pan cook the strawberries with the sugar for 2-3 minutes until they release juice stirring gently using a spatula. Combine the cornstarch with the jam and stir until smooth then stir into the strawberries mixture. Cook for another minute. Remove from the heat and fold in the almond flour. Set aside to cool completely before making the turnovers. Meanwhile preheat the oven to 400 F/ 200 C/ gas mark 6.
Roll out your pastry into a 4 mm thick rectangle and using a pizza cutter cut into 6 (13 cm/5 inch) squares. Work with one square at a time and keep the rest in the fridge on top of parchment paper (chilled pastry is easier to work with).
To make a turnover place a tablespoon of the filling in the centre of each square, lightly brush the edges with the milk then fold one corner over the opposite one sticking the edges together (do this thoroughly). If the pastry sticks to your fingertips dip them in the oat milk. Seal the edges further by pressing down with a fork. Place ready turnovers back in the fridge on top of the baking sheet. Once you’ve made all the turnovers refrigerate them for a further 10 minutes.
Remove from the fridge and score the top of each turnover in 3 places then brush the tops evenly with a little milk. Scatter the remaining sugar over the top and bake in the centre of the oven for 18-20 minutes until nicely browned.
Remove from the oven and set aside for 5 minutes then transfer the turnovers onto a cooling rack.
Ensure your oven is very hot. Preheat it for at least 15 minutes.
Use a flexible spatula (such as silicon) to gently stir the filling mixture so the strawberries keep their shape.
Cool the filling mixture completely before making the turnovers. I like to cool it down for a few minutes then put in the freezer for the final 5 minutes or so.
Start preparing the pastry while you are waiting for the filling to cool.
Work with one pastry square at a time and keep the rest refrigerated (chilled pastry is easier to work with). For best results refrigerate ready turnovers (before scoring) for 10 extra minutes (your turnovers will be super crisp and flaky).
Make sure you score the top of each turnover in 3 places to allow the steam to escape.
Stick the edges of the turnovers really well then go over with a fork.
Bake in the centre of the oven for 18-20 minutes until golden/lightly browned. If after 18 minutes your turnovers are still a little pale bake them for a few extra minutes. If you undercook your turnovers they may not keep their shape as well and become a little soggy inside.