1. Preheat your oven to 350°F (175°C) and line a 9×13 inch baking pan with parchment paper.
2. In a large bowl, combine the flour, oats, granulated sugar, brown sugar, baking powder, and salt. Stir to blend.
3. Add the melted butter and vanilla extract to the dry ingredients. Mix until the mixture resembles coarse crumbs. My abuela always taught me to use my hands for this step to feel the texture.
4. Press about two-thirds of the crumb mixture into the bottom of the prepared pan, creating an even layer.
5. In another bowl, toss the diced apples with the caramel sauce and cinnamon until well coated.
6. Spread the apple mixture evenly over the crumb crust in the pan.
7. Sprinkle the remaining crumb mixture over the top of the apples, pressing down lightly.
8. Bake in the preheated oven for 35-40 minutes, or until the top is golden brown and the apples are tender.
9. Allow the bars to cool in the pan for at least 30 minutes before cutting into squares.

Remember, patience is key here. Letting the bars cool ensures they hold their shape when sliced.