Beat 3/4 c sugar and shortening until light and fluffy. Add egg and beat well. Stir together 2 c of flour, baking powder, and salt. Add flour mixture and milk alternately to beaten mixture. Beat till smooth after each addition. Spread in greased 8x8x2 or 9x9x2 baking pan. Top with blueberries. Combine the remaining 1/2 c flour, 1/2 c sugar, and cinnamon. Cut in butter or margarine until crumbly. Sprinkle over blueberries. Bake at 350 for 45 to 50 minutes. Cut into squares and serve warm.