1-First, preheat your oven to 350°F (175°C) and place a rack in the center. Grease and line an 8×8-inch baking pan to ensure easy removal and cleanup perhaps with foil or parchment paper. In a bowl, beat together the granulated sugar, brown sugar, flour, baking powder, and salt until combined, then add the cubed butter and vanilla extract. Beat until the mixture becomes crumbly with butter pieces about pebble-sized, and refrigerate it for the best texture.

2-Next, prepare the apple filling by mixing the sliced apples with flour, sugar, cinnamon, and lemon juice in another bowl. Press 2 cups of the crumb mixture firmly into the pan to form the crust, then spread the apple filling evenly over it. Stir the oats and cinnamon into the remaining crumb mixture and sprinkle this over the apples as a topping. Using two different apple varieties can add depth to the flavor, so feel free to mix it up.

3-Cover the pan with foil and bake for 30 minutes, then remove the foil and bake for an additional 25 to 30 minutes until the topping is golden brown and the apples are tender. Allow the bars to cool on a wire rack before drizzling with caramel sauce and serving. For convenience, you can use pre-made caramel sauce if you’re short on time. This recipe serves 9 to 12, making it perfect for sharing with friends and family.