Preheat the oven to 325°F and lightly grease a small 4-inch springform pan or oven-safe ramekin.
Combine the almond flour with a teaspoon of water in a small bowl, stirring until it reaches a sandy, clumpable texture.
Press the almond mixture firmly into the bottom of the prepared pan to form an even crust layer.
Whisk the Greek yogurt, whey protein isolate, egg, vanilla extract, stevia, and lemon zest together in a medium bowl until the batter is completely smooth and no lumps remain.
Pour the cheesecake batter over the almond crust and smooth the top with a spatula.
Bake for 25 to 30 minutes or until the edges are set and the center slightly jiggles when the pan is gently shaken.
Remove from the oven and allow the cheesecake to cool to room temperature on a wire rack.
Refrigerate for at least 3 hours, or preferably overnight, to allow the cake to fully set and develop a firm, velvety texture.