Custard Filling
["3 Tbsp. flour", "1/2 c. sugar", "1/8 tsp. salt", "1 c. milk", "1 egg", "1/2 tsp. vanilla", "1 tsp. butter"]
["Combine dry ingredients thoroughly.", "Add milk and eggs.", "Cook over boiling water until thick like pudding.", "Add vanilla and butter.", "Mix well.", "Cool."]
["flour", "sugar", "salt", "milk", "egg", "vanilla", "butter"]