Preheat oven to 350. In a large bowl,cream butter and brown sugar until fluffy. Beat in the eggs and vanilla. In another bowl,whisk the flour,baking powder,spices and salt; gradually beat into creamed mixture. Spread into a greased 9-in. Square baking pan.

Mix topping ingredients; sprinkle over top. Bake 35-40 minutes or until set and golden brown. Cool in pan on wire rack. Cut into bars.