Line the bottom of an 8-inch springform pan with aluminum foil. You can use just one sheet of foil to cover the entire pan, just make sure the raised sides go up to at least 1.5 inches.
Combine graham cracker crumbs *, sugar, and lemon zest in a small bowl. Add butter and mix until all the crumbs are moistened and a thick, crumbly paste forms. Pour graham crumb paste onto the lined springform pan. Level and press to the bottom of the pan using a rubber spatula and neatly taper at the edge. Cover the pan with plastic wrap and place in the freezer for 15 minutes.
Mix gelatin crystals and 1/4 cup water in a small bowl and allow to bloom for 5 minutes. Heat the other 1/4 cup water for 30 seconds in the microwave on high and pour into the gelatin bloom. Stir to dissolve, and allow to cool.
Place cream cheese, granulated sugar and lemon juice in a large bowl of a stand mixer fitted with a paddle attachment (you can use a hand mixer as well). Mix on low to break down the cream cheese for 30 seconds, and increase to medium speed for another 1 minute. Scrape the sides of the bowl and add sour cream, whipping cream, Greek yogurt and vanilla extract. Mix on medium for 30 seconds, scrape the sides, and then up the speed to medium-high for 2 minutes, until smooth and fluffy.
Starting on low speed again, pour gelatin into the cream cheese mixture. Then bump up to medium speed for a minute, scraping the sides of the bowl after 30 seconds.
Pour into the springform pan with crust and level with a spatula. Tap pan lightly against the counter to get rid of air bubbles. Cover with plastic wrap and refrigerate for at least 3 hours, preferably overnight.
Unhinge the springform pan and remove it from the cake. Carefully slide off the cake, still on the foil, onto a serving plate. You can tear out the sides of the aluminum foil or carefully slide it side to side to unstick it from the crust, and remove. To smooth the sides of the cake, slide the smooth edge of a table knife around it to create a smooth even surface. Pour your topping/s of choice before serving. It gets even better after 2 or 3 days!
Store in the fridge, wrapped in plastic wrap to prevent the exposed areas from drying out.