Preheat oven to 350°. Line and grease a 8×8” baking dish with foil.
First the filling -
In a large pan combine the apples, sugar, and cinnamon. Cook over medium heat, stirring occasionally, for 5-7 minutes, until apples are tender but still firm. Add the cornstarch and lemon juice and continue cooking, stirring constantly for 3 minutes or until thickened. Remove from heat.
To make the base, in a medium bowl combine flour, sugar and salt. Mix well. Cut the butter into the flour mixture using a pastry blender until it resembles breadcrumbs. Press the mixture into the bottom of the prepared pan. Bake for 10-12 minutes, until lightly browned around the edges. Remove from the oven. Top with the cooked apple mixture.
In a separate bowl combine all ingredients for the topping. It will be crumbly. Sprinkle over the apple layer. Bake for 25-30 minutes or until golden brown. Remove from the oven and allow to cool. I put mine in the refrigerator for easier cutting.
Keep in the refrigerator (you can heat it in the microwave for 15 seconds before serving - Yum!