Prep the filling: Mix cream cheese + 30 g sweetener + egg yolk + vanilla until smooth. Scoop into 18 small balls (~12 g each) and freeze 15–20 minutes.
Preheat & sift: Preheat oven to 175°C / 350°F. Line baking sheet with parchment. Whisk almond flour, coconut flour, cream of tartar, baking soda, and salt.
Cream butter & sweetener: Beat softened butter with 80 g powdered sweetener until light. Add eggs one at a time and vanilla.
Make dough: Fold dry mix into wet until combined. Dough should be soft but pliable. If too sticky, chill 10 minutes.
Assemble: Flatten dough balls, insert a frozen cheesecake ball, wrap and seal, then roll in cinnamon coating. Place on tray and chill 15–20 minutes.
Bake: Bake 12–14 minutes until edges are set. Cool 10 minutes on sheet, then transfer to rack.
Serve: Best warm or at room temperature. Store as directed.