Prep the pan: Line a 12-cup muffin tin with paper liners. Lightly mist the liners with cooking spray to prevent sticking.
Preheat the oven to 325°F (160°C).
Make the crust: In a bowl, combine graham crumbs, melted butter, sweetener, and a pinch of salt. Mix until the texture resembles damp sand and holds together when pressed.
Press the crust: Divide the crumb mixture evenly among the 12 liners (about 1 tablespoon each). Press down firmly with the bottom of a small glass or spoon to compact.
Soften the cream cheese: In a large bowl, beat the cream cheese with a hand mixer on medium speed until smooth and lump-free, about 1 minute.
Scrape the bowl.
Build the filling: Add Greek yogurt, sugar or sweetener, vanilla, lemon juice, lemon zest, and salt. Beat on low until combined, then on medium until silky, 30–45 seconds. Avoid overwhipping.
Add the eggs: Beat in the egg and egg white on low, just until incorporated.
Overmixing can add air and cause cracks.
Fill the cups: Spoon the batter over each crust, filling about 3/4 full. Smooth the tops with the back of a spoon if needed.
Bake gently: Bake for 16–20 minutes, until the edges are set and the centers have a slight jiggle. They will finish setting as they cool.
Cool gradually: Let the cheesecakes cool in the pan for 20 minutes, then transfer to a wire rack to reach room temperature.
Chill to set: Refrigerate for at least 2 hours (4 is better) until fully set and creamy.
Top with berries: Toss berries with lemon juice and a touch of honey or sweetener.
Spoon over the chilled cups just before serving. Garnish with mint if you like.