Preheat oven to 350F. Grease a 9x13 inch baking pan then line with parchment paper with a slight overhang on each side. Set aside.
In a large bowl, combine melted butter, 1 cup granulated sugar and ¼ cup packed brown sugar until smooth and incorporated.
Add the egg, ube jam and 2 tbsp ube extract and stir until combined.
Sift 2½ cups flour, 1 tsp baking powder and 1 tsp salt into your ube mixture and gently stir until no significant streaks of flour remain (do not over mix). The batter will be thick.
Gently fold in 1 cup white chocolate chips until evenly distributed.
Transfer into prepared pan and spread around evenly with a spatula.
Bake for 30-40 minutes or until a toothpick inserted in the middle comes out with minimal dry crumbs.
Cool in the pan for 20 minutes, remove from pan to cool completely, then cut into bars.
