Peel, core, and thinly slice your 8 cups apples Place the sliced apples directly into a 9x13 inch baking dish (or a similar sized dish).
In a medium bowl, whisk together the ¾ cup granulated sugar, ¼ cup all-purpose flour, 1 teaspoon ground cinnamon, and ½ teaspoon ground nutmeg
Sprinkle the dry mixture evenly over the sliced apples. Add the1 teaspoon vanilla extract and 1 tablespoon fresh lemon juice. Toss everything gently until the apples are thoroughly coated in the spiced mixture. Spread the apples into an even layer in the bottom of the baking dish.
In the same bowl (no need to wash!), combine the 1 cup all-purpose flour, 1 cup rolled oats, 1 cup light brown sugar, and ½ teaspoon ground nutmeg and 1 teaspoon ground cinnamon. Stir them together well.
Add the cubed cold ½ cup butter to the dry ingredients. Using a pastry blender, two knives, or your fingers, cut the butter into the mixture until coarse, pea-sized crumbs form. Do not overmix; you want the topping to remain crumbly.
Sprinkle the crisp topping evenly over the apple filling, ensuring the apples are mostly covered.
Bake in a preheated oven at 375°F (190°C) for 35 to 45 minutes, or until the topping is golden brown and the apple filling is bubbling thickly around the edges.
Let the crisp cool for about 10 minutes to allow the filling to set slightly. Serve immediately, while still warm, topped with vanilla ice cream for the classic experience!