Place apple slices in bowl.

Add 3/4 cup water and lemon juice and toss to prevent browning.

In a saucepan, whisk together cornstarch and 1/4 cup water until blended.

Add cinnamon and sugar. Whisk until blended.

Add contents of apple slice bowl to saucepan and cook over low heat until apples are tender.

Allow to cool before putting in crust.