Preheat oven to 425 degrees F. Prepare a 9 x 9 inch round pie pan with unbaked pie crust. I like to crinkle the crust with my fingers at the top for decoration (this is optional). You can also crimp the edges of the crust with a fork. Poke a few holes around the crust with a fork to help prevent air bubbles. Parbake the crust for 18 minutes, be sure to add a pie shield or cover the edges with foil to prevent burning halfway during baking. Remove from oven then reduce the oven heat to 375 degrees F.
In a large frying pan or large skillet, add apple slices, sugars, spices, lemon juice, vanilla extract, milk, butter and flour. Mix and let cook for 10-15 minutes or until apples are tender. Remove from heat and make the streusel topping.
To make the streusel topping, add all of the ingredients into a small or medium bowl and use a pastry cutter or a fork until crumbly pieces form.
Assemble the pie by spooning the cooked apple mixture into the parbaked pie crust, then sprinkle the crumble topping all over the top, spreading to the edges in an even layer.
Place pie on a baking sheet and bake for 35-40 minutes, then let the pie cool on a wire rack for at least 3 hours to set and thicken before serving (optional). Slice and top with a scoop of vanilla ice cream or whipped cream. Enjoy!