In a mixing bowl, combine almond flour, melted butter, and powdered erythritol. Stir until the mixture forms a crumbly texture.
Press the crust mixture evenly into the bottom of a springform pan, smoothing it out with the back of a spoon or a flat glass. Refrigerate the crust to set while you prepare the cheesecake filling.
In a large bowl, beat the softened cream cheese with an electric hand mixer until smooth.
Add the powdered erythritol, vanilla extract, and lemon juice (if using), then mix until well combined.
Gradually pour in the heavy cream, continuing to beat the mixture until it becomes light and fluffy.
Spread the cream cheese filling evenly over the chilled crust, smoothing the top with a spatula.
Cover the pan with plastic wrap and refrigerate for at least 4-6 hours or overnight for the best texture.
Once set, carefully remove the cheesecake from the springform pan, slice, and serve with your favorite keto-friendly toppings, like fresh berries or sugar-free syrup.