Preheat oven to 350°F. Line a 9×13-inch baking pan with parchment paper so that there is an overhang on either side. This will make it easier to remove the blondies from the pan. Grease lightly with cooking spray and set aside.

In a large bowl, cream together the butter and brown sugar until light and fluffy, 3 minutes. Add in the peanut butter and stir until combined. Then add the eggs one at a time, mixing well after each addition. Stir in the vanilla.

Add the flour, baking powder and salt to the bowl and stir until just combined. Transfer the mixture to the prepared pan and spread out into an even layer.

Using a spoon, dollop the strawberry preserves on top, spacing them out randomly. Do not swirl. Sprinkle the chopped peanuts on top and bake until a toothpick, inserted in the middle, comes out clean, 28 to 32 minutes. Remove the pan from the oven and allow to cool completely. Using the parchment paper lift the blondies from the pan. Then slice into 18 even pieces. Serve immediately or store in an airtight container. Enjoy!