Preheat oven to 350° F. Line bottom of a 9″ springform pan with parchment and coat sides of pan with butter. Set aside.
To make crust: In medium bowl, mix almond meal, cinnamon, sugar substitute, and salt. Add butter and mix well. In small bowl, beat egg white with whisk until foamy and add to almond mixture. Mix well and pat into bottom of pan. Bake 10 to 12 minutes or until lightly browned. If crust rises, poke it with a fork and press it down. Let cool.
Increase oven temperature to 500° F.
To make filling: In food processor or large bowl, beat cream cheese until smooth. Add sour cream, sugar substitute, lemon juice, vanilla extract, and salt. Mix well. Blend in egg yolks. Add eggs, one at a time, blending well after each addition. Scrape bowl frequently while mixing.
Place springform pan on baking sheet. Carefully pour filling over crust. Bake 5 minutes. Reduce oven temperature to 200° F. Continue baking 1 1/2 hours. Do not open door while baking. When done, cheesecake should still look soft in center.
Remove from oven and run a knife around outside of your keto cheesecake. Let cool on rack to room temperature. Serve immediately or chill.