HK's Cinnamon Cake

3/4 cup butter 
1 cup sugar
1 egg
1 1/2 tsp. cinnamon 
1 1/2 cups flour
1 1/2 cups whipping cream
1 tsp. vanilla
Cream butter until soft. Gradually add 3/4 cup sugar; beat until light 
and fluffy. Add egg; beat well. Add cinnamon and flour; mix well. 
Spread about 1/3 of batter on ungreased baking sheet into a rectangle 
about 10 by 12 inches. Bake in 400 degree oven 8 minutes or until 
lightly browned. Remove from oven; let stand a few minutes. Cut cake 
into 3 equal rectangles; transfer to cooling rack. Repeat process 
with remaining batter. Whip cream until stiff. Fold in 1/4 cup sugar 
and vanilla. Spread a thin layer of whipped cream; top with other cake. 
Serve immediately. Makes 8 servings.