4 tablespoons butter unsalted plus more for the pan
1.5 teaspoons vanilla extract
0.3 cup walnuts chopped
Equipment
bowl
frying pan
oven
knife
whisk
baking pan
aluminum foil
microwave
Directions
Preheat the oven to 350 degrees F. Line an 8-inch-square baking pan with foil, pressing it into the corners and up the sides; leave an overhang on 2 sides. Butter the foil.
Put 4 tablespoons butter and the brown sugar in a large microwave-safe bowl. Microwave until the butter is melted, about 1 minute. Stir in the vanilla.
Let cool slightly, then stir in the egg.
Whisk the flour, salt and baking powder in a small bowl. Stir into the butter mixture. Stir in the butterscotch chips and nuts and spread the batter in the pan. Drop dollops of jam on top and swirl with a knife.
Bake until set, 20 to 25 minutes.
Let cool 15 minutes on a rack, then lift the foil and transfer the blondies to the rack to cool completely.