Step 1

Preheat oven to 350°, with a rack in the center of the oven. Line an 8x8 baking pan with foil or parchment paper, grease it, and set aside.

Step 2

Using a hand mixer or stand mixer fitted with the paddle attachment, beat granulated sugar, brown sugar, flour, baking powder, and salt until combined. Add cubed butter and vanilla and beat until the butter is broken up into small irregular pieces. If necessary, use your fingers to rub the butter into the flour. Once the mixture is crumbly and the butter is the size of pebbles, place in the refrigerator while you prepare the filling.

Step 3

In a separate bowl, combine all ingredients for apple filling. Stir until well combined.

Step 4

Scoop 2 cups (loosely measured, not packed) of the crust/topping and dump it into the baking dish. Use the back of the measuring cup to press the mixture into an even layer to form the crust. Set aside the remaining crumb mixture.

Step 5

Add the apples on top of the crust. Arrange them in tight layers, overlapping the pieces.

Step 6

Stir ⅓ cup oats and ¼ teaspoon cinnamon into the reserved crumb mixture. Sprinkle the topping over the apples pressing some of it together to form clumps.

Step 7

Cover with foil and bake for 30 minutes. Remove the foil and bake for another 25-30 minutes, until the topping is light golden brown and the apples are tender (insert a sharp knife to check). Place pan on a wire rack to cool. Drizzle with caramel sauce. Serve warm, room temperature, or chilled. Top with ice cream and caramel sauce. Note: The bars will cut more neatly if chilled.