Combine the butter, erythritol, coconut, almond flour and salt in a medium bowl and mix until a dough forms.

Press the dough into a pie plate, going all the way up the sides.

Bake the crust at 350 degrees (F) for 15 minutes, or until golden brown.

Melt the butter in a small saucepan on low heat.

Remove from heat and whisk in 1/2 cup sweetener, lemon juice, and lemon zest until dissolved. Whisk in the egg yolks and return to the stove over low heat.

Whisk continually until the curd starts to thicken.

Remove from the heat and strain into a small bowl. Chill.

In a large bowl, whip the heavy whipping cream, xanthan gum, and 1 Tbsp sweetener together until stiff peaks form.

Fold 1/3 of the whipped cream mixture into the chilled lemon curd until combined.

Add the lightened lemon curd mixture to the remaining whipped cream and gently fold together until fully combined, but still fluffy.

Spoon the filling into the cooled pie crust. Garnish with additional whipped cream and lemon zest if desired.

Serve chilled. Will keep up to a week in the refrigerator.