Mama's Chocolate Pie

Mama's Chocolate Pie
1 1/2 cups sugar
1/2 cup flour
1/4 cup cocoa
dash of salt
2tbsp butter
4 eggs, seperated
2 1/4 cups milk
1tsp vanilla
Mix sugar, flour, cocoa and salt. Add slightly beaten egg yolks and 1/4 cup milk. Mix thoroughly. Add remaining milk, butter and vanilla. Cook over medium heat in a heavy saucepan, stirring continuously until thick. Pour into baked 9 5/8in pie shell. Add meringue and bake at 350 until slightly brown.