Separate 3 eggs, reserving whites for meringue in medium bowl. Beat yolks and set aside.
Combine flour, sugar, salt, water, and milk. Cook in microwave for 3 minutes then stir. Continue cooking at 1 1/2 minute intervals, stirring after each. When thick, add a small amount of hot filling mixture to beaten egg yolks, then into hot mixture and cook until thick. Remove from heat and stir in vanilla and butter. Set aside to cool while making meringue. May substitute 4 tsp. cocoa leaving out 4 tsp. of the flour for chocolate pie. May add 2 sliced bananas. May add 1 to 1 1/2 C. of coconut.