Butterscotch Cream Pie

2 cups firmly packed light brown sugar
3/4 cup all-purpose flour
4 egg yolks
2 1/2 cups half-and-half
1 tbsp butter or margarine
1 tsp vanilla extract
1 baked 9-inch pie shell
Whipped cream

Combine sugar, flour and egg yolks in a large saucepan. Gradually add half-and-half, stirring well. Add butter; cook over medium heat, stirring constantly, until thickened. Stir in vanilla; cool. Pour into pie shell; chill several hours or until set. Garnish with whipped cream.