Combine beer, soda, and cream of tartar in a
medium-sized bowl. Set aside.
Beat sugar and eggs together until combined. Add butter, flour and beer mixture, beating until ingredients are combined and the batter is smooth.
Turn into a greased 13x9-inch baking pan. Sprinkle with Streusel Topping and bake in preheated 375-degree oven 45 minutes or until cake tests done.
Combine flour, sugar and butter until mixture resembles fine crumbs. Sprinkle over cake batter.