Preheat oven to 325 degrees F. Grease and flour 3 (8 or 9-inch) cake pans.
For the cake:
Mix together the flour, cinnamon and sugar in a large bowl. Add the remaining ingredients and blend well with a handheld electric mixer for about 2 minutes. Pour batter into prepared pans. Bake for 25 to 30 minutes, or until golden brown. Allow to cool in pan for 5 minutes. Invert onto lint-free dishcloth, or waxed paper, and allow to cool completely.
For the frosting:
Mix all ingredients with handheld electric mixer and blend until smooth and creamy.
Frost layers, top, and sides of cooled cake.