Step 1

Preheat oven to 350°F (175°C). Grease and line a 9×13-inch baking pan.

Step 2

Whisk melted butter, brown sugar, and granulated sugar. Add eggs and vanilla. Mix until smooth.

Step 3

Gradually fold in flour, baking powder, and salt. Stir in butterscotch chips and white chocolate chips (optional).

Step 4

Pour batter into the pan and bake for 25-30 minutes. Let cool.

Step 5

Drizzle melted butterscotch chips over cooled blondies. Slice and serve.