Phase 1: Prepare the Pan and Oatmeal Crust Base

1. 1. Preheat Oven and Prepare Pan: Preheat your oven to 350°F (175°C). Grease an 8×8 inch or 9×9 inch square baking pan. For easier removal and cleanup, line the pan with parchment paper, leaving an overhang on two opposite sides to act as “handles.” Grease the parchment paper as well.

1. 1. Combine Dry Crust Ingredients: In a medium to large mixing bowl, whisk together the all-purpose flour, old-fashioned rolled oats, packed light brown sugar, baking soda, and salt (if using).

1. 1. Add Melted Butter: Pour the melted butter over the dry ingredients. Stir with a fork or your fingertips until the mixture is well combined and forms coarse crumbs. It should be uniformly moistened.

1. 1. Press Crust Base: Take slightly more than half (about ⅔) of the oatmeal crumb mixture and press it firmly and evenly into the bottom of your prepared baking pan. Use the bottom of a glass or a measuring cup to help create a compact, level base. Set the remaining crumb mixture aside for the topping.

1. 1. Par-Bake the Crust (Optional but Recommended for Crispier Base): Bake the crust base for 10 minutes. This step helps create a slightly firmer base that holds up better to the caramel. If you’re short on time, you can skip this, but the base might be a bit softer.

Phase 2: Create and Add the Caramel Chocolate Layer

1. 1. Melt the Caramels: While the crust is par-baking (or if you skipped it, while you prepare this), unwrap the caramels and place them in a microwave-safe bowl along with the heavy cream (or evaporated milk).

      • • Microwave Method: Microwave on high in 30-second intervals, stirring well after each interval, until the caramels are completely melted and the mixture is smooth. This usually takes 1.5 to 2.5 minutes total. Be careful not to overheat.
      • • Stovetop Method: Alternatively, combine caramels and cream in a small saucepan over low heat. Stir constantly until melted and smooth.

1. 1. Pour Caramel Over Crust: Once the caramel is smooth, carefully pour it evenly over the (par-baked, if you did that step, or unbaked) crust base in the pan. Spread it gently with a spatula if needed to cover the entire surface.

1. 1. Sprinkle Chocolate Chips: Immediately sprinkle the chocolate chips evenly over the hot caramel layer. If you’re using nuts, you can sprinkle them on now as well.

Phase 3: Add Topping and Bake

1. 1. Add Remaining Crumb Topping: Take the reserved oatmeal crumb mixture and crumble it evenly over the chocolate chip and caramel layer. Gently pat it down very slightly, but don’t press too hard – you want a nice, crumbly topping.

1. 1. Bake: Transfer the pan to the preheated oven. Bake for 18-25 minutes (for an 8×8 pan, a 9×9 pan might take slightly less time). The topping should be golden brown, and the caramel around the edges should be bubbly. The center might still look a little soft, which is okay. Be careful not to overbake, as this can make the caramel hard once cooled.

Phase 4: Cooling (The Most Crucial Step!)

1. 1. Cool Completely: This is THE most important step for successful Carmelitas. Remove the pan from the oven and place it on a wire rack to cool completely to room temperature. This will take at least 2-3 hours.

1. 1. Chill for Easier Cutting (Highly Recommended): Once cooled to room temperature, cover the pan with plastic wrap and transfer it to the refrigerator for at least another 1-2 hours, or even overnight. Chilling solidifies the caramel and chocolate, making the bars much easier to cut into neat squares without becoming a gooey mess.

1. 1. Cut and Serve: Once thoroughly chilled, use the parchment paper overhangs to lift the entire block of Carmelitas out of the pan and onto a cutting board. Cut into squares using a large, sharp knife. If the caramel is very firm, you might let them sit at room temperature for 15-20 minutes before cutting, or run your knife under hot water and dry it between cuts for cleaner slices.