1 stick butter, melted
1 cup light brown sugar
1 tsp pure vanilla extract
1 cup all purpose flour
pinch of salt
1/2 cup butterscotch chips
1/2 cup semi-sweet chocolate chips
Preheat oven to 350 degrees. Spray an 8x8 baking pan with non-stick cooking spray. Line with parchment paper with a 1/2 inch overhang on each end. Spray parchment paper with non-stick cooking spray.
In a large stand mixer, beat together the butter and brown sugar until smooth. Add the egg and vanilla and mix to incorporate. Add the flour and salt and mix just until combined. Stir in the butterscotch and semi-sweet chocolate chips.
Pour into prepared pan. Bake for 20-25 minutes, or until set around the edges. Let cool in the pan on a wire rack while you prepare the brown sugar frosting.
Brown Sugar (Penuche) Frosting:
1/2 cup butter
1 cup light brown sugar, packed
1/4 cup milk
2 cups powdered sugar, sifted
In a medium saucepan, melt the butter. Add the brown sugar. Bring to a boil, lower heat to medium, and continue to boil for 2 minutes, stirring constantly. Add the milk and bring to a boil, stirring constantly (it will bubble up). Turn off the heat and let cool to lukewarm. Gradually add the sifted powdered sugar and whisk until combined.
Pour frosting over the blondies and let cool completely. When cool, lift blondies out of pan and cut into squares. Enjoy!