In a small saucepan, combine chopped strawberries, allulose, and lemon juice. Cook over medium heat for about 8 minutes, stirring occasionally, until syrupy and bubbly. Remove from heat and cool for 10 minutes.

Whisk together cornstarch and water in a small bowl until smooth. Gradually stir into cooled strawberry filling and return to medium heat. Cook for 2 minutes until thickened. Cool further.

In a medium mixing bowl, combine softened cream cheese, allulose, vanilla extract, and salt. Blend until smooth and creamy. Chill in the refrigerator for about 10 minutes.

In a microwave-safe bowl, combine shredded mozzarella and cream cheese. Microwave on high for 1 minute, stir, then microwave for 30 seconds more. Mix in almond flour and baking powder, then knead in egg until smooth.

Preheat oven to 400°F (205°C) and line a baking sheet with parchment. Roll dough between two sheets of parchment to about ⅛-inch thick. Cut into 8 equal rectangles.

On one half of each rectangle, spoon about 1 tablespoon of cheesecake filling followed by 1 tablespoon of cooled strawberry filling. Fold over, seal edges, and crimp with a fork.

Brush a beaten egg over the tops of the turnovers. Optionally sprinkle with allulose. Bake for 16 minutes until golden. Watch to prevent over-browning.

Remove from oven and cool on the baking sheet for 10 minutes. Serve warm or at room temperature.