Preheat oven to 375°F and lightly grease a 9-inch pie dish.
In a large bowl, toss 4 cups of peeled and sliced apples with 1/4 cup of granulated sugar, 2 tablespoons of cornstarch, 1 teaspoon of cinnamon, and a pinch of salt.
In a small saucepan, bring 2 cups of fresh or frozen raspberries, 1/4 cup of water, and 1/4 cup of granulated sugar to a boil over medium-high heat, stirring occasionally. Reduce heat and simmer until slightly thickened, about 15 minutes.
Roll out one pie crust and fit it into the prepared pie dish, trimming and crimping the edges. Spoon the apple mixture evenly over the crust, leaving some juice behind.
Pour the raspberry sauce over the apple layer, spreading it gently with a spatula.
Roll out the second pie crust and place it over the filling, cutting some slits on top. Brush the crust with some beaten egg and sprinkle some coarse sugar over it.
Bake the pie for 25 to 30 minutes, or until golden and bubbly. Let it cool slightly before serving with whipped cream or vanilla ice cream. Enjoy!