Lightly toast the almond flour in a skillet over medium heat for about 3-5 minutes, stirring frequently until golden brown. Remove from heat and mix with monk fruit sweetener, sea salt, and cinnamon in a bowl. Add melted butter and mix until combined. Press into the bottom of a springform pan and freeze for 30 minutes to set.

Whip the heavy cream in a large bowl using an electric mixer until stiff peaks form, about 3-4 minutes. Refrigerate the whipped cream. In another bowl, beat the cream cheese with monk fruit sweetener until smooth and creamy, about 2-3 minutes. Mix in sour cream, vanilla extract, and lemon juice until well combined.

Gently fold the whipped cream into the cream cheese mixture using a spatula until no streaks are visible.

Spread the cream cheese filling evenly over the crust in the springform pan. Cover with plastic wrap and refrigerate for at least 8 hours or overnight.

After chilling, carefully remove the springform sides. Slice with a sharp knife and garnish with fresh berries or sugar-free chocolate sauce as desired.