In a large mixing bowl, combine your cookie crumbs, sweetener, and melted butter and mix together, until combined. Transfer into a 9-inch pie dish and refrigerate.
In a large mixing bowl, beat together the cream cheese until smooth. Add the condensed milk and lime juice and beat until combined. Add the heavy cream and beat everything together until thick and creamy.
Transfer the filling onto the chilled pie crust and refrigerate overnight, to thicken.
Once set, prepare the topping. Beat together the heavy cream with the powdered sweetener until light and fluffy. Spread over the top of the pie and add sliced limes, to decorate.
* I've tried this with shortbread cookies, peanut butter cookies, and almond butter cookies. TO STORE: This key lime pie should always be stored in the refrigerator, covered, for up to 2 weeks. TO FREEZE: Place slices of the pie in a shallow container and store them in the freezer for up to 6 months.