Preheat the oven to 350˚F. Spray an 8x8 inch pan with cooking spray and line the pan with parchment paper.
In a medium sized bowl, add in the flour, cinnamon, ginger, nutmeg, salt, and baking powder. Mix with a whisk until the ingredients are evenly distributed.
In a large bowl, add in the melted butter, vegetable oil, granulated sugar, and dark brown sugar. Mix with a whisk until the ingredients are combined. Add in the eggs and vanilla extract and mix until fully combined. Pour in the flour mix and gently mix it into the wet ingredients with a rubber spatula. Add in the white chocolate chips and gently fold them into the batter until they are evenly distributed throughout.
Pour the blondie batter into the prepared pan and spread it into an even layer. Bake it in the oven for about 30 minutes. When a toothpick is inserted into the center of the blondie it should come out with a few moist crumbs. The edges should be set and the center should be slightly soft. Allow the blondies to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely. Use a knife to cut them into 9 even squares. Enjoy!