Directions:
In a small bowl, cream butter, sugar & lemon zest until light & fluffy. Beat in egg. Combine the flour, baking powder & salt; add to creamed mixture alternately with milk, beating well after each addition. Fold in blueberries. Pour into a greased 9 inch square pan.
For topping, in a small bowl, combine the sugar, flour & cinnamon; cut in butter until crumbly. Sprinkle over blueberry mixture.
Bake at 375 for 45 mins or until a knife inserted near the center comes out clean. Do a zig zag of icing on cake. Cool on a wire rack.
Buttercream Icing
Ingredients:
1/2 cup solid veg. shortening
1 stick margarine
1/ tsp clear vanilla extract
4 cups sifted confectioners' sugar
2 tbsp milk
Directions:
In a lg. bowl, cream shortening & butter w/ electric mixer. Add vanilla. Gradually add sugar, one cup at a time, beating well on medium spped. Scrape sides & bottom of the bowl often. When all sugar has been mixed in, icing will appear dry. Add milk & beat at medium speed until light & fluffy. Keep bowl covered until ready for use.