Preheat oven to 450° and spray a mini muffin pan with nonstick cooking spray.
In a large saucepan over low heat, bring water, sugar, cornstarch, cinnamon, and lemon juice to a boil, stirring constantly.
Continue stirring until sauce thickens, about 3-4 minutes.
Add diced apples, stir and let simmer for 8-10 minutes, stirring occasionally.
Remove from heat and let cool completely. Set aside.
Roll out pie crust on a floured surface and use a ⅓ cup measuring cup to cut out circles for the crust and place in mini muffin pan.
Place 1-2 tsp of apple filling in each pie crust.
Bake for 15-18 minutes or until edges of pie crust are golden brown.
Optional: top with caramel sauce or vanilla ice cream and serve warm.