• Preheat the oven to 350℉. Spray a deep 9x13 baking dish with cooking spray. Set aside.

Make The Apple Filling

• Peel, core, and cut the apples into small chunks, about 1-inch in size. Place the chopped apples into a large bowl. Immediately add the lemon juice over top of the apples and stir to combine. This will help prevent them from browning too quickly while you prepare everything else.
  10 cups small chopped Granny Smith apples, 2 teaspoons lemon juice
• Sprinkle the vanilla extract over top the apples and stir to coat. 
  2 teaspoons vanilla extract
• In a small mixing bowl, whisk together the granulated sugar, flour, ground cinnamon, kosher salt, and nutmeg until combined. Add this cinnamon-sugar mixture to the apples and toss to combine until all the apples are coated. 
  3/4 cup granulated sugar, 2 tablespoons all-purpose flour, 2 teaspoons ground cinnamon, ½ teaspoon kosher salt, ¼ teaspoon ground nutmeg
• Transfer the apple mixture into the prepared baking dish in an even layer.

Make The Apple Crisp Topping

• In a mixing bowl, add the old-fashioned oats, all-purpose flour, light brown sugar, ground cinnamon, and kosher salt. Stir with a whisk to combine. 
  1½ cups old-fashioned whole oats, 1 cup all-purpose flour, 1 cup packed light brown sugar, 1 teaspoon ground cinnamon, ¼ teaspoon kosher salt
• Add the chilled cubed butter and use your clean hands, or a pastry cutter or pastry blender, to cut in the butter until the mixture resembles coarse crumbs. 
  12 tablespoons cold butter
• Evenly sprinkle the oatmeal crisp topping over the apples for a nice thick layer. 

Bake The Apple Crisp

• Bake for 50-55 minutes or until the topping is golden brown and the apples are bubbling around the edges.

  ^{*If the crisp topping is getting too browned, loosely lay a piece of aluminum foil over top the casserole dish for the last 15 minutes of the bake time.} 
• Remove the apple crisp from the oven and allow it cool for about 10 minutes. Serve a scoop of warm apple crisp topped with a scoop of vanilla bean ice cream. Enjoy!