Brown-Butter Toffee Blondies

OK, this photo is actually from last fall when I made these bars, but I'm out of sweets and making these tomorrow! I cut this recipe out of my local newspaper, but not sure where it originally came from...

10 tablespoons butter

1 cup brown sugar, packed

1/4 cup granulated sugar

1 egg

1+1/2 teaspoons vanilla

1 cup + 2 tablespoons flour

3/4 teaspoon salt

3/4 teaspoon baking powder

1/2 cup (or more) chopped walnuts

1/2 cup toffee bits

Preheat oven to 350 degrees. Grease a 9" x 9" pan, then put down a 9" strip of parchment with overhang on either side (so you can lift the bars out later) and grease that as well. Melt butter over medium heat until it turns golden brown; let cool. Combine butter, sugars, egg & vanilla and beat until light and fluffy. Stir in dry ingredients, then nuts and toffee bits. Pile into pan and bake for 35-40 minutes. Cool completely in the pan, then lift parchment out. Cut into 16 squares (or 9, or 4, or not at all). Store in an airtight container.