Prep the pan. Line the bottom of a 9-inch springform pan with parchment. Lightly grease the sides. Preheat oven to 325°F (163°C).
Set a rack in the lower-middle position.
Make the crust. In a bowl, mix crumbs, almond flour, cocoa, sweetener, and salt. Stir in melted butter or oil until the texture resembles damp sand. Press firmly into the pan, going slightly up the sides.
Bake 8–10 minutes, then cool while you make the filling.
Soften and smooth. Beat cream cheese on medium speed until velvety and lump-free, about 2 minutes. Scrape the bowl well. Add Greek yogurt and beat again until smooth.
Sweeten it right. Add sugar, zero-calorie sweetener, vanilla, and salt.
Beat on low until combined. Taste and adjust sweetness now, before adding eggs and chocolate.
Add the chocolate power. Beat in cocoa and protein powder on low. Pour in the melted, slightly cooled dark chocolate and mix just until uniform.
If the batter seems too thick, add 1–3 tablespoons milk to loosen. Avoid overmixing.
Eggs go last. Add eggs one at a time on low speed, mixing just until incorporated. Overbeating adds air, which can cause cracks.
Pour and smooth. Pour filling over the crust.
Tap the pan gently on the counter to release air bubbles. Run a knife through the batter in a few swirls to pop any hidden pockets of air.
Create a gentle bake. Place the springform on a sheet pan. Bake 45–55 minutes, until the edges are set and the center wobbles like gelatin, not soup.
If it’s browning too quickly, tent loosely with foil.
Cool it right. Turn off the oven, crack the door slightly, and let the cheesecake rest inside for 45 minutes. This gradual cooldown helps prevent cracks.
Chill completely. Transfer to a rack to reach room temperature. Then cover and refrigerate at least 6 hours, preferably overnight.
The texture improves as it chills.
Slice and serve. Run a thin knife around the edge before unlatching the springform. Warm a sharp knife under hot water, wipe dry, and slice clean wedges. Add berries, chocolate shavings, or a light drizzle if you like.