• Preheat the oven to 350F

Make the crust:

• By hand in a bowl or in a food processor, mix together all the crust ingredients until a dough forms. Press the crust into the bottom and up the sides of a 10-inch glass pie pan. Bake for 12 to 14 minutes, until lightly browned. Set aside.

Make the filling:

• Melt the butter in a heavy saucepan over low heat. Whisk in the powdered sweetener, Key lime juice, and lime zest. When the sweetener is dissolved, whisk in the egg yolks.
• Keep the heat low and whisk constantly until the mixture has thickened. Remove from the heat and strain through a fine-mesh sieve to remove the zest. Refrigerate until cool, at least 1 hour.
• In a large bowl, use a hand mixer or stand mixer to whip the heavy cream. As it begins to thicken, add the vanilla extract and liquid sweetener and continue whipping until the mixture is thick and creamy.
• Gently fold the whipped cream into the chilled lime juice mixture so that the filling remains fluffy.
• Use a spatula to fill the crust with the filling and smooth the filling edge to edge. Place the pie in the refrigerator to chill for at least 4 hours or overnight before serving.
• Garnish with lime slices, lime zest, and/or freshly whipped cream, if desired