1/2 c. butter
1/2 c. flour
3 c. milk
3 bananas, sliced
1/2 c. sugar
1 tsp. vanilla
1 box vanilla wafers
1 large Cool Whip

Melt butter, then add flour. Stir in 1 cup of milk at a time. Stir until it bubbles. Add sugar; stir well. Remove from heat, then add vanilla. Pour over vanilla wafers and bananas. Chill. Put Cool Whip on for topping.