Preheat the oven to 350 degrees F. In a large mixing bowl, combine the flour, both sugars, pumpkin pie spice, baking powder, and salt. Mix well. Then whisk in the melted butter, pumpkin puree, egg, and vanilla. Whisk until smooth.
Stir the white chocolate chips into the batter. Then scoop the batter into a 9.5-inch Swiss Diamond Fry Pan and smooth out the top. Bake for 25-30 minutes. Check by inserting a toothpick into the center of the blondies. If it comes out clean, remove from the oven.
Cool for 5 minutes. Shake the skillet gently to loosen the edges and slide the entire skillet pumpkin blondie recipe out of the fry pan. Cut and serve with ice cream!
You can also use an 8-inch nonstick skillet, but the cooking time will be about 30-35 minutes. If you use any brand of skillet other than Swiss Diamond, you must grease the bottom before adding the batter.