Combine brown sugar and cinnamon; cut in butter until crumbly and well mixed. Set aside. Sift together flour, baking powder and salt. Cream shortening in mixer bowl. Gradually beat in sugar. Add egg an vanilla; beat well. Stir in flour mixture by hand alternately with milk, starting and ending with flour mixture. Pour into greased 8" square pan. Sprinkle with brown mixture. Bake in 425 F oven 30 to 35 minutes or until golden brown. Serve warm.