Ingredients

• 3 tablespoons margarine
• 1/4 cup sugar
• 1/4 teaspoon salt
• 1 large egg yolk
• 3 tablespoons fresh lemon juice
• 1 teaspoon grated lemon zest
• 1/2 teaspoon ground cinnamon
• 3 large sweet potatoes (1-1/2 pounds total), cooked, peeled, and mashed
• 1 cup fat-free evaporated milk
• 3 large egg whites
• 1 prepared 9-inch pie shell, unbaked

Directions

1. Preheat the oven to 350 degrees F. Beat together the margarine, sugar, and salt in a large bowl. Add the egg yolk, lemon juice, lemon zest, and cinnamon; mix well. Stir in the sweet potatoes and milk; mix again.
2. Beat the egg whites to stiff peaks and fold them into the sweet potato mixture; pour into the pie shell.
3. Bake for about 40 to 50 minutes, or until a knife inserted in the center comes out clean. Cool and cut the pie in 8 equal slices.