Combine almond flour, melted butter, Erythritol, lemon zest, vanilla extract, and salt in a small bowl.
Butter the bottom of a 9-9.5" springform pan. Press crust mixture into the bottom of the pan in an even layer.
Bake crust for 10 minutes or until golden brown.
Remove pan from oven and reduce heat to 325 degrees.
Using an electric mixer, beat the cream cheese and erythritol until fluffy, for about 3 minutes.
Add sour cream, lemon juice and vanilla then mix until smooth.
Add eggs, one at a time, beating until combined. (Tip: Don't over-blend)
Pour cheesecake mixture over the baked almond flour crust.
Raspberry Swirl (Optional Step)
Process raspberries in a food processor until smooth, about 30 seconds. Pass puree through a fine sieve into a small bowl.
Add erythritol to the seeded raspberry puree. Mix well, and then transfer puree to a ziplock bag. Cut a small corner off the ziplock bag to use for piping.
Pipe teaspoon sized dots of the raspberry sauce on top of the cheesecake. With a wooden skewer or toothpick, swirl the sauce into filling. To make raspberry swirls, pipe dots onto the cheesecake in a circle, pull wooden toothpick in swirls through the sauce.
Bake at 325 for 1 hour. The cake should look slightly wobbly in the center still, but it will set as it cools. To minimize cracks, try not to open the oven as the cheesecake is cooking.
Remove cake from oven and let come to room temp for at least one hour.
Let cool in the fridge for at least 4-6 hours, then run a knife around the edge of the cake before removing from springform pan. If your cheesecake cracks, smooth the top with a warm spatula for a quick and easy repair!
Total Carbs: 28 g - Fiber: 2 g - Erythritol: 23 g = Net: 3.5 g