Prepare the Crust: Preheat your oven to 350°F (175°C).

In a medium bowl, combine almond flour, erythritol, melted butter, and vanilla extract. Mix until well combined.

Press the mixture into the bottom of a springform pan to form an even crust. Bake for 10 minutes, then remove from the oven and set aside.

In a large bowl, beat the softened cream cheese until smooth. Add the erythritol and beat until combined.

Mix in the sour cream, lemon juice, lemon zest, and vanilla extract until smooth.

Add the eggs one at a time, beating well after each addition.

Pour the cheesecake filling over the pre-baked crust in the springform pan.

Bake the Cheesecake: Place the springform pan into a larger baking dish filled with hot water (water bath). Bake in the preheated oven for 50-60 minutes, or until the center is set and the edges are lightly golden.

Turn off the oven and leave the cheesecake inside with the door slightly open for 1 hour. Remove from the oven and refrigerate for at least 4 hours or overnight.

Prepare the Meringue: In a clean, dry bowl, beat the egg whites with cream of tartar until soft peaks form. Gradually add the erythritol while continuing to beat until stiff, glossy peaks form.

Spread or pipe the meringue over the chilled cheesecake. Use a spatula or spoon to create peaks and swirls.

Use a kitchen torch to lightly brown the meringue, or place under a broiler for a few minutes (watch carefully to avoid burning).

Allow the meringue to cool slightly before slicing and serving.