In a medium pot, add the strawberries, sugar, and vanilla. Stir together and simmer on low-medium for 10 minutes. Remove from the stove and allow to cool completely.
In the meantime, roll out two puff pastry sheets. Cut out 4 equal squares, for a total of 8 squares.
Add one tablespoon of the strawberry jam mixture to the center of each square. Dip your fingers in a bowl of water and wet the edges of each square. Fold one corner of a square to the other to form a triangle, then press the sides together. Repeat for all squares until you have 8 triangles.
Use the tines of a fork to press down around the edges to further seal the edges of each triangle together.
Combine the egg and remaining water in a small bowl and whisk together to create an egg wash. Use a pastry brush to brush the egg wash over the tops of each triangle.
Spray the interior of your air fryer with non-aerosol avocado oil spray. Place the prepared turnover triangles onto the air fryer basket or tray(s). Depending on the size of your air fryer, you may need to work in batches.
Air fry at 400°F for 15 to 18 minutes, until the tops and edges are golden brown and the puff pastry is cooked through. Garnish with additional sliced strawberries, if desired.
OPTIONAL: MAKE THE ICING GLAZE
In a large bowl or glass measuring cup with spout, combine 1 ½ cups powdered sugar with cream or milk and vanilla. Whisk together. Add more powdered sugar if you want it to be thicker; add more milk if you want the glaze to be thinner. Drizzle over the pastries and allow the icing glaze to set.
Notes
Storage: Allow to cool completely. Then store in an airtight container or resealable plastic bag in the refrigerator for up to 5 days or freezer for up to one month. From the fridge: reheat in the air fryer for 2 to 3 minutes. From frozen: allow to thaw completely at room temperature, then reheat in the air fryer for 2 to 3 minutes.