Lemony Sweet Potato Pie

Ingredients

3 egg yolks
1 c sugar
1 t flour
1 1/2 c milk
1/2 lemon extract
1 t lemon peel
2 t butter
1 c sweet potatoes
1 pie shell
9 sweetened whipped cream

Instructions

Bake 10 minutes, then reduce heat to 325'F. and continue to bake until pie is firm. Serve warm topped with well-chilled sweetened whipping cream.