• Preheat oven to 375F and line a square 9×9 baking pan with parchment paper.
• Peel and thinly slice your apples and set aside in a medium sized mixing bowl.

Crumb Base/Topping

• In a large bowl whisk together the rolled oats, brown sugar, flour, and cinnamon.
  3/4 C brown sugar, 1 C all purpose flour, 1/2 tsp ground cinnamon, 1 & 1/4 C rolled oats
• Add the melted butter into the dry ingredients and mix till everything is combined. It will have crumbly texture.
  3/4 C salted butter
• Set aside 1/2 C of the crumb mixture and pour the rest into your pan. Evenly spread and press the crumb mixture down with your hands so it forms a solid crust.

Apple Filling

• To the sliced apples add in the white sugar, cornstarch, cinnamon, and lemon juice. Mix well to coat all the apple slices.
  2 C thinly sliced and peeled apples, 2 tsp cornstarch, 1 tbsp lemon juice, 1 tsp ground cinnamon, 1 tbsp white sugar
• Spread the apple mixture over the crumb base in your pan.
• Top with the remaining 1/2 of crumb mixture you set aside. You just want to sprinkle it above the apples.
• Bake for 28 minutes or the edges are golden brown.
• It is important to let the bars fully cool in the pan to room temperature before removing them and slicing. The bars need time to stiffen up. If you try and slice them before they cool they'll fall apart.