1. Preheat your oven to 350°F (175°C) and line a 9×13-inch baking pan with parchment paper, leaving some overhang for easy removal later.
2. In a large mixing bowl, cream together the softened butter and granulated sugar until the mixture is light and fluffy. This usually takes about 3-4 minutes with an electric mixer. I like to think of this step as the foundation of the magic—getting this right means your crust will be perfectly tender yet crisp.
3. Mix in the flour and salt until just combined. The dough will be crumbly but should hold together when pressed.
4. Press about two-thirds of this dough evenly into the prepared pan, creating a smooth, firm base. Use your fingers or the bottom of a glass to get it nice and compact.
5. Bake the crust in the preheated oven for 15-18 minutes, or until it’s lightly golden around the edges. I always keep an eye on it here, because that golden color means the crust is ready to hold all that caramel goodness.
6. While the crust bakes, combine the brown sugar, sweetened condensed milk, caramel bits, and vanilla extract in a medium saucepan over medium heat. Stir continuously until the mixture melts and thickens, about 5-7 minutes. If you’re adding nuts, stir them in now as well.
7. Pour the warm caramel mixture over the baked crust, spreading it evenly with a spatula.
8. Crumble the remaining third of the dough over the caramel layer, sprinkling it evenly to create that signature “crunch” topping.
9. Return the pan to the oven and bake for an additional 20-25 minutes, until the topping is golden and the caramel is bubbling gently at the edges.
10. Allow the bars to cool completely in the pan on a wire rack. This step is crucial—I’ve learned that patience here means clean, easy slices that hold their shape.
11. Once cooled, use the parchment paper overhang to lift the bars out of the pan. Cut into squares or rectangles and serve.

One little tip from my kitchen: if you want super clean cuts, warm your knife under hot water, wipe it dry, and then slice. It glides through the caramel layer beautifully without sticking.