These fudgy peanut butter blondies with a blueberry swirl are the perfect mashup of chewy brownie and fruity dessert. Once you try them, you won't be able to stop.
Preheat oven to 350°F. Grease an 8x8-inch baking pan.
In a large bowl, beat butter, granulated sugar, and brown sugar until creamy. Mix in peanut butter.
Add eggs one at a time, beating well after each addition; stir in vanilla.
Whisk together flour, baking powder, and salt in a separate bowl; gradually stir into batter.
Spread batter into prepared pan. Drop blueberry jam by spoonfuls on top and swirl with a toothpick.
Bake 25-30 minutes until top is lightly golden. Let cool completely before cutting.