Step 1: Preheat the Oven
Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or a silicone mat.

Step 2: Prepare the Apple Filling
In a small saucepan over medium heat, melt the butter and add the diced apples. Stir in brown sugar, cinnamon, vanilla, lemon juice, and a pinch of salt. Cook for about 5–7 minutes until the apples soften slightly and the mixture starts to thicken. Sprinkle in the flour and stir to combine. Let the filling cool while you prepare the pastry.

Step 3: Roll and Cut the Puff Pastry
On a lightly floured surface, roll out the thawed puff pastry just enough to even out the creases. Cut it into 6 equal squares using a sharp knife or pizza cutter.

Step 4: Fill the Turnovers
Spoon a generous tablespoon of the apple mixture into the center of each square. Be careful not to overfill, or the turnovers may burst open while baking.

Step 5: Fold and Seal
Fold each square into a triangle, bringing one corner over to the opposite to form a diagonal. Press the edges together with your fingers, then seal them tightly using the tines of a fork.

Step 6: Brush and Vent
Transfer the turnovers to the prepared baking sheet. Brush the tops lightly with plant-based milk to help them turn golden brown. Use a sharp knife to cut a small slit or two in the top of each turnover to allow steam to escape.

Step 7: Bake
Bake for 18–22 minutes, or until the turnovers are puffed and golden brown. Remove from the oven and allow them to cool for 10 minutes before serving.

Step 8: Optional Glaze
If desired, mix powdered sugar with a little plant-based milk to create a glaze. Drizzle over the slightly cooled turnovers for extra sweetness and shine.