Mix cereal with 1/2 cup sugar, the instant coffee and cinnamon; set aside. Mix flour with 1 cup sugar, the baking soda, baking powder and salt in large mixer bowl. Add sour cream, butter, eggs and vanilla. Blend at low speed with electric mixer, then beat for 1 minute at medium speed. Spread one third of the batter in a greased 8 inch square pan; sprinkle with half of the cereal mixture. Repeat layers and top with remaining batter. Bake at 350 degrees for 45 to 50 minutes, or until tooth pick inserted into the center comes out clean. Cool in pan; spread with coffee glaze. Coffee glaze: Gradually blend 2 tb cooled brewed Maxwell House coffee into 1 1/2 cups sifted confectioners sugar. Makes enough to glaze the top of an 8 or 9 inch square cake or 10 inch tube cake.