Lemon Sponge Pie
["2 lemons (rind and juice)", "1/2 c. shortening", "2 c. sugar", "1/2 tsp. salt", "6 1/2 Tbsp. flour", "2 c. milk", "6 eggs, separated"]
["Cream sugar and shortening.", "Add egg yolks and mix well.", "Add lemon rind and juice.", "Add flour.", "Mix; add milk.", "Beat egg whites until very stiff and fold into mixture.", "Put into 2 unbaked 9-inch pie shells and bake 10 minutes at 400\u00b0, then 30 minutes at 350\u00b0 on lower oven rack."]
["lemons", "shortening", "sugar", "salt", "flour", "milk", "eggs"]