1 tsp. flour
2 tsp. cornstarch
1/4 tsp. alum (powder)
1/3 c. water

In top of double boiler, mix dry ingredients. Add water slowly, stirring out lumps. Cook over low heat, stirring constantly. Remove from heat when paste begins to thicken; it will thicken more as it cools. Keep covered. Add water to thin when necessary.