Preheat oven to 325. Spray the sides of a 9.5-inch springform pan with nonstick baking spray. Wrap the sides of the pan with a strip of parchment paper.
In a mixing bowl, add the graham cracker crumbs, sugar, and melted butter. Stir until the butter coats all of the crumbs.
Press the crumbs evenly into the bottom and up the sides of the prepared pan.
Place in the oven and let bake for 15 minutes. Remove from the oven and let cool while you work on the cheesecake filling.
In a mixing bowl, add in the cream cheese and granulated sugar. Beat with a hand mixer on medium until completely incorporated. Scrape the sides and bottom of the bowl and mix again to avoid any lumps of cream cheese in your batter.
Add in the eggs one at a time. Beat in each egg completely before adding the next. Scrape down the bowl after adding each egg.
Add in the key lime juice and sweetened condensed milk. Mix until incorporated.
Just before adding the cheesecake mixture, line the outside of the springform pan with two layers of heavy-duty tin foil.
Pour the cheesecake filling on top of the crust.
Place the springform pan in a slightly larger baking pan. Fill the outer pan with about an inch of water.
Place in the oven at 325 degrees and let bake for 1 hour and 15 minutes or until done. To make sure the cheesecake is done, gently give it a wiggle. If it slightly jiggles in JUST the middle like jello, then it's done. If it jiggles all over, it needs to bake longer. Turn off the heat and crack the oven door slightly. Let it cool in the oven for 1 to 2 hours until it reaches room temperature and then place in the fridge to chill overnight.
In a mixing bowl, add in the heavy cream. Beat until soft peaks form.
Add in the powdered sugar. Continue to beat until it becomes thick and stiff peaks form.
Add the whipped cream into a piping bag with a 1M tip. Pipe the whipped cream on top of the cheesecake.
Sprinkle the zest on top of the cheesecake.
Add the quartered pieces of lime in between the swirls of whipped cream.
If the limes are damp, dry them off before adding them to the whipped cream.