LEMON CURD: Combine natural sweetener, lemon juice, 4 eggs and lemon peel in heavy medium saucepan and whisk to blend; add coconut oil. Whisk constantly over medium heat until mixture thickens and coats back of spoon thickly (do not boil), about 12 minutes.

Pour mixture through strainer into medium bowl. Place bowl in larger bowl filled with ice water and whisk occasionally until lemon curd is cooled completely, about 15 minutes. Can be made 1 day ahead.

Place curd into pie crust and chill. Serve with whipped cream if desired.