Line 13x9-inch pan with foil, with ends of foil extending over sides. Combine flour, baking powder and 1 tsp. spice. Beat butter, 1 cup sugar and 1/4 cup molasses in large bowl with mixer until blended. Gradually add flour mixture, mixing well after each addition. Remove 1 cup dough; place in medium bowl. Add oats; mix with fingers or fork until mixture resembles coarse crumbs. Set aside. Press remaining dough onto bottom of prepared pan.