Caramel-Peanut Pie
["2 c. sugar, divided", "1 c. boiling water", "2 Tbsp. all-purpose flour", "5 eggs, separated", "2 c. milk", "1 c. chopped peanuts", "1 tsp. vanilla extract", "2 baked (9-inch) pastry shells", "1/4 c. sugar"]
["Place", "1", "cup", "sugar in heavy skillet; cook over medium heat, stirring constantly, until sugar melts and forms a light brown syrup.", "Reduce heat to low;", "gradually add boiling water in", "a slow", "stream,", "stirring", "constantly", "with a wire whisk. Remove from heat."]
["sugar", "boiling water", "flour", "eggs", "milk", "peanuts", "vanilla extract", "pastry shells", "sugar"]