Preheat oven to 350°F. Line and 8-inch x 8-inch baking pan with parchment paper and set aside.
In a medium bowl, whisk together flour, baking powder, salt, cinnamon, ginger, cardamom, cloves and nutmeg.
In a large bowl, mix together melted butter and brown sugar until combined. Whisk in egg, egg yolk, and vanilla. Mix in dry ingredients until just combined. Gently fold in white chocolate chips.
Pour batter into prepared pan and smooth the surface. Bake for 28-30 minutes, or until the blondies are golden brown and the edges have set, but the center is still soft. Let cool. Cut into squares and enjoy.