Start by preheating the oven to 350°F (180° C). Line a 9" / 23cm springform pan with parchment paper, and then grease and flour the paper to make sure the crust stays intact.
To make the crust, mix the almond flour, melted butter, erythritol, and vanilla extract in a mixing bowl to get a slightly crumbly dough. Press the dough into the bottom of the prepared pan. Bake for about 10-12 minutes and let it cool it down to room temperature (this is to prevent the crust from cracking due to sudden temperature change).
* Pro tip: If you’re concerned about presentation and want to even out the crust’s thickness, carefully press the dough on all sides (including the bottom) with your fingers. You can use a knife to carefully remove the excess dough.