Gluten Free Apple Crumble

Ingredients:

3 medium Granny Smith apples, peeled and diced (approx 4 cups chopped)
¼ cup granulated sugar
¼ cup raisins
¼ teaspoon cinnamon powder
¼ teaspoon powdered nutmeg or allspice
3/4 cup orange juice
2 tablespoons cornstarch
1 tablespoon grated orange zest
½ teaspoon vanilla extract (optional)