Vinegar Pie - cooking recipe

Ingredients

1 (9-inch) pie crust, baked
1 c. white sugar
3 egg yolks
1 Tbsp. unsalted butter
3 Tbsp. distilled white vinegar
6 Tbsp. white sugar
1/4 c. sifted all-purpose flour
1 c. water
1/8 tsp. salt
1/4 tsp. lemon extract
3 egg whites

Preparation

Mix flour with 1/2 cup sugar. Add water gradually and cook on top of double boiler for 15 minutes, stirring constantly or until thick. Combine remaining 1/2 cup of sugar with egg yolks and salt and mix well. Add the hot flour mixture to the yolk mixture. Return to double boiler and cook 3 more minutes or until mixture is thick. Add butter, extract and vinegar. Mix well and remove from heat.
Place plastic on top of custard.