Apple Yam Pie

Source: North Carolina Sweet Potatoe Recipes

2 C. Sifted all-purpose flour 
1 tsp. Salt 
2/3 C. Shortening 
2 Slightly beaten egg yolks 
2 tbls. Cold water 
1 tbls. Lemon juice 

Sift together first 2 ingredients into a large mixing bowl. Cut in the shortening to the size of small peas. Combine next 3 ingredients. Sprinkle over flour mixture, stirring with fork until dough is moist enough to hold together. Shape 2/3 of dough into a square. Roll out on floured surface to a 14x10-inch rectangle. Fit loosely into 10x6-inch pan. (May be rolled to fit other pans.)