Definition: In this task, you have to generate the title of the recipe given its required ingredients and directions.
Input: ingredients:  '1 1/2 cups cooked or canned mashed sweet potatoes', '3 Tbsp. butter', '2 eggs', '1/4 tsp. salt', '1 cup sugar', '1 tsp. lemon flavoring', '1 cup milk', '1/2 cup chopped black walnuts', '1 - 9 inch unbaked pie shell',<sep> directions: 'Mix all ingredients well. Pour into unbaked pie shell and bake in 350° oven for 30 minutes or until firm.'

Sweet Potato Black Walnut Pie