Step 1

To a medium saucepan, add butter, powdered sugar free sweetener and heavy cream. Bring to boil over medium heat. Reduce heat and let simmer for 30 minutes to thicken. Remove from heat and pour into a mason jar or similar container. Let cool at room temperature for about 30 minutes before transferring in the refrigerator for 2 hours.

Step 2

In a medium glass bowl, whisk together lime zest with egg yolks. Whisk for about 2 minutes. Add sweetened condensed milk prepared earlier and stir until smooth.

Step 3

Stirring by hand with a whisk, very slowly stir lime juice into the filling mixture. Set aside for 30 minutes to thicken slightly. Move onto the pie crust.

Step 4

To a food processer, pulse together almond flour, coconut flour, xanthan gum and salt. Add in cubed butter, cream cheese, egg and vinegar. Pulse until just combined.

Step 5

Roll out pie crust in between two sheets of parchment paper until the crust is a large circle about 1/8 - 1/4 inch thick. Refrigerate dough for 15 minutes. Remove the top layer of parchment paper and place pie plate upside down over the dough. Slide a hand under the bottom layer of parchment paper, place other hand on top of pie plate and flip over. Remove the parchment paper and press the pie dough into the pie pan. Bake at 350 degrees for 8 minutes. Lower heat to 325 degrees and let cool for about 20 minutes.

Step 6

Pour lime filling into cooked and cooled pie crust. Bake at 325 degrees for 15-20 minutes. Bake until edges are slightly set but the center jiggles like jello. Refrigerate for 2-3 hours or until set.

Step 7

In a small bowl, add heavy cream and powdered sweetener. Beat with an electric mixer until stiff peaks form. Top on key lime pie. Top pie with additional lime zest if desired.