01 - Preheat oven to 350°F. Line a 9x9-inch baking pan with parchment paper, leaving overhang for easy removal.
02 - Combine flour, sugar, and salt in a large bowl. Cut in cold butter using a pastry cutter or fingers until crumbly. Stir in vanilla extract.
03 - Reserve 1 1/2 cups of mixture for topping. Press remaining dough evenly into pan bottom to form crust.
04 - Bake crust for 12 minutes, then remove from oven.
05 - Toss apple slices with lemon juice. Add sugar, flour, and cinnamon, tossing to coat evenly.
06 - Spread apple mixture over hot crust. Drizzle caramel sauce over apples. Sprinkle reserved crumb mixture evenly on top.
07 - Bake for 28-32 minutes until topping is light golden brown and apples are tender.
08 - Cool completely in pan. Lift out using parchment and cut into bars.