Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish or line it with parchment paper.
In a large mixing bowl, whisk together the 1 cup vegetable oil and 1 cup brown sugar until smooth and combined. Add the 2 eggs, one at a time, beating well after each addition. Stir in the 2 tsp vanilla extract and 1/2 cup pumpkin puree until fully incorporated.
1 cup vegetable oil, 1 cup brown sugar, 2 eggs, 2 tsp vanilla extract, 1/2 cup pumpkin puree
In a separate bowl, whisk together the 2 3/4 cup all purpose flour, 2 tsp cornstarch, 2 tsp ground cinnamon, 1/2 tsp ground nutmeg, 1/2 tsp ground cloves, 1/2 tsp ground ginger, and 1/2 tsp baking powder.
2 3/4 cup all purpose flour, 2 tsp cornstarch, 2 tsp ground cinnamon, 1/2 tsp ground nutmeg, 1/2 tsp ground cloves, 1/2 tsp ground ginger, 1/2 tsp baking powder
Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix, as this can make the blondies dense.
Gently fold the 1 cup white chocolate chips into the batter until evenly distributed.
1 cup white chocolate chips
Pour the batter into the prepared baking dish and spread it out evenly. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs.
Allow the blondies to cool completely in the pan before slicing into squares.