Preheat your oven to 350°F (175°C).
Line a 9x13-inch baking pan with parchment paper, leaving some overhang.
Cream together the softened butter and light brown sugar using an electric mixer until smooth and fluffy.
Add the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract.
In another bowl, whisk together the all-purpose flour, baking powder, and salt. Gradually add the dry mixture to the wet ingredients, stirring just until combined.
Spread half of the batter evenly into the prepared baking pan.
Evenly distribute the halved Rolo candies over the batter layer.
Dollop the dulce de leche over the Rolo candies and swirl it gently into the batter.
Spread the remaining batter over the dulce de leche layer.
Bake for 25-30 minutes, or until golden brown and a toothpick inserted into the center comes out clean.
Allow the bars to cool in the pan for about 10 minutes, then lift them out using the parchment paper and let cool completely on a wire rack before cutting into squares.
