Nonstick baking spray
1 1/2 cups all-purpose flour, plus more for dusting
3/4 cup firmly-packed brown sugar
2 sticks butter
One 8-ounce package frozen cranberries
1/2 cup chopped walnuts
3/4 cup granulated sugar
1 teaspoon vanilla extract
2 large eggs, yolks separated from whites
2 teaspoons baking powder
1/4 teaspoon salt
3/4 cup milk