To Make the Crust
Preheat your oven to 375°F / 190°C. Prepare a 9- or 10-inch springform pan by greasing the bottom and sides with butter, or by lining the bottom with a parchment paper circle and greasing the sides.
In a medium bowl, combine the almond flour, crushed pecans, granular erythritol, and cubed salted butter. Use a fork or your fingers to mix until the are well combined and the mixture is crumbly.
Press the crust mixture evenly and firmly into the bottom of the prepared pan.
Par-bake the crust for 12 to 15 minutes, until the edges are golden brown.
Remove the crust from the oven and reduce the oven temperature to 325°F / 165°C. Allow the crust to cool completely on a wire rack while you prepare the filling.
To Make the Filling
In a large mixing bowl, use a hand mixer on medium speed to beat the softened cream cheese until it is completely smooth and fluffy, with no lumps.
With the mixer still on medium, gradually add the confectioners'-style erythritol and beat until it is fully incorporated and the mixture is smooth.
Add the room-temperature eggs one at a time, mixing on low speed just until combined. Be sure to scrape down the sides and bottom of the bowl after each addition.
Gently beat in the sour cream, followed by the lemon juice and vanilla extract, mixing on low speed just until combined. The final batter should be thick, smooth, and creamy.
To Assemble and Bake
Tightly wrap the outside of the cooled springform pan with one or two large sheets of heavy-duty aluminum foil. This creates a waterproof seal for the water bath.
Pour the cheesecake filling over the cooled crust and smooth the top with an offset spatula.
Place the foil-wrapped springform pan into a large roasting pan. Carefully pour hot water into the roasting pan until it reaches halfway up the sides of the springform pan.
Bake for 1 hour and 30 minutes, or until the edges are set but the center still has a slight jiggle. The top may be lightly browned.
Carefully remove the springform pan from the water bath and remove the foil.
Let the cheesecake cool completely on a wire rack at room temperature.
Once cooled, cover the cheesecake and refrigerate for at least 8 hours, or preferably overnight, to allow it to fully set.
To serve, run a thin knife around the edge of the pan before releasing the springform latch.
Slice and enjoy! Leftovers can be stored in an airtight container in the refrigerator for up to 5 days.
Don't overmix after adding the eggs.
Mix on low speed and only until just combined. Overbeating incorporates too much air, which causes the cheesecake to puff up and then crack as it cools.
Cool it down slowly. Abrupt temperature changes are a primary cause of cracks.
After the baking time is up, turn off the oven, crack the door open, and let the cheesecake cool inside for one hour before moving it to a wire rack.
