Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish and set aside.

In a large mixing bowl, combine melted unsalted butter and packed light brown sugar until well blended.

Add all-purpose flour, old-fashioned rolled oats, baking soda, and salt to the bowl with the butter and sugar mixture. Stir until the ingredients are evenly combined and form a crumbly dough.

Press half of the oatmeal cookie dough into the bottom of the prepared baking dish, forming an even layer.

Pour caramel sauce or dulce de leche over the layer of cookie dough, spreading it evenly with a spatula.

Sprinkle semi-sweet chocolate chips and chopped pecans over the caramel layer.

Crumble the remaining oatmeal cookie dough over the top of the caramel, chocolate chips, and pecans, forming an additional layer.

Bake the Carmelitas in the preheated oven for 25-30 minutes, or until the edges are golden brown and the center is set.

Remove the baking dish from the oven and let the Carmelitas cool completely in the pan on a wire rack.

Once cooled, cut the Carmelitas into squares or bars using a sharp knife.

Serve the Carmelitas at room temperature and enjoy every delicious bite!