Prep the pan: Line a 12-cup muffin tin with paper liners.
Lightly mist the liners with cooking spray so the cups release cleanly.
Heat the oven: Preheat to 325°F (163°C). A moderate oven helps prevent cracks and rubbery texture.
Make the crust (optional): Stir graham crumbs, melted butter, sugar, and a pinch of salt until sandy and moist. Divide about 1 tablespoon per liner.
Press down firmly with the bottom of a small glass.
Par-bake crust: Bake crusts for 5–6 minutes until lightly set. Let cool while you mix the filling.
Soften the cream cheese: Beat light cream cheese with a hand mixer on medium until smooth and fluffy, about 1–2 minutes. Scrape the bowl.
Add yogurt and vanilla: Mix in Greek yogurt and vanilla until silky.
Keep the mixer on low to avoid whipping in too much air.
Sweeten and thicken: Add sugar or sweetener, protein powder, cornstarch, lemon juice, and salt. Blend just until smooth. Taste and adjust sweetness.
Add the eggs: Beat in eggs one at a time on low speed, stopping once combined.
Overmixing can cause cracks.
Fill the cups: Divide the batter evenly among the liners, filling each about 3/4 full.
Bake gently: Bake 15–18 minutes. The centers should look slightly wobbly but not liquid. They will set as they cool.
Cool slowly: Turn off the oven, crack the door, and let the cheesecakes sit for 10 minutes.
Then move the pan to a rack and cool to room temperature.
Chill to set: Cover and refrigerate at least 3 hours, preferably overnight. Add toppings just before serving.