Butterscotch Pie
["1 baked pie crust", "1 c. brown sugar, packed", "4 Tbsp. unsalted butter", "3 Tbsp. water", "3 Tbsp. flour", "1 1/2 c. milk", "3 eggs, separated", "pinch of cream of tartar", "3 Tbsp. sugar"]
["In a heavy saucepan, combine brown sugar, 2 tablespoons butter and water; cook over medium heat to boiling.", "Reduce heat and cook gently until caramel is dark and syrup-like.", "Remove from heat and set aside.", "Melt remaining 2 tablespoons butter in saucepan over medium heat.", "Remove from heat; whisk in flour until smooth.", "Return to heat and cook, stirring constantly.", "Pour in milk and heat to boiling."]
["crust", "brown sugar", "unsalted butter", "water", "flour", "milk", "eggs", "cream of tartar", "sugar"]