Sweet Potato Pie
["3 c. sweet potatoes", "1/4 c. butter", "1 c. sugar", "1 tsp. lemon extract", "1 egg, beaten", "1/2 c. evaporated milk", "unbaked pastry shell"]
["Boil the potatoes in their jackets until done; peel and mash. Add butter, sugar and lemon extract.", "Combine the beaten egg and milk.", "Mix with the potatoes until blended.", "Pour into the pastry shell and bake at 375\u00b0 for 1 hour."]
["sweet potatoes", "butter", "sugar", "lemon extract", "egg", "milk", "pastry shell"]