Delicious Microwave Chocolate Pie

1 baked pie crust
¼ to ½ cup flour
3 Tbsp cocoa
1 ¼ cup sugar
2 egg yolks
2 cups milk
¼ cup margarine
1 tsp vanilla

Mix together flour, cocoa, sugar, and add enough hot water to mix well. Add egg yolks and milk. Cook in microwave safe bowl for 3 minutes. Stir then cook for 3
more minutes. Add margarine and vanilla. Mix well and pour into prepared crust. Can top with meringue or with cool whip.