Preheat the oven to 400°F. Press two large overlapping sheets of parchment paper into a 9-inch springform pan, letting the paper rise about 2 inches above the rim with plenty of rustic folds, then set the pan on a baking sheet.
In a large bowl, beat the cream cheese and sugar on medium speed until completely smooth and glossy, about 2 minutes, scraping down the bowl as needed.
Reduce the speed to low and beat in the eggs one at a time, mixing just until each one disappears. Add the yogurt, heavy cream and vanilla and mix until smooth.
Sift the protein powder, cornstarch and salt over the batter and mix on low until just combined. Tap the bowl firmly on the counter a few times to release air bubbles, then pour the batter into the lined pan.
Bake for 40 to 50 minutes, until the top is a deep, dark caramelized brown and the edges are puffed and set. The center should still jiggle like a loose custard when you gently shake the pan, which is exactly what gives this cheesecake its creamy middle.
Cool the cheesecake in the pan at room temperature for 1 hour. It will sink and settle as it cools, which is completely normal for this style.Refrigerate for at least 6 hours or overnight.
Release the springform, peel away the parchment and slice. For the creamiest texture, let the slices sit at room temperature for 20 minutes before serving, with fresh berries on the side if you like.