Using 18-inch heavy-duty aluminum foil, wrap the outside of your springform pan with 4 sheets of foil. You can use regular foil, but it may take a couple more sheets to ensure the water does not get into your pan.
Place the wrapped pan in a deep roasting pan. You can alternatively use a baking sheet, so long as the sides are about 2 inches deep.
Using very hot water, add water to the baking sheet until there is about 1 ½ inch of water around the springform pan. With the rack in the lower 3rd of the oven, carefully move the pan into the oven.
Bake at 325 degrees Fahrenheit for 1-1 ½ hours. After about an hour of baking, check the cheesecake’s consistency. A slight jiggle of the pan (while still in the oven) should tell you if it’s ready or needs more time. The cheesecake should be only slightly jiggly, but not liquid. If it still seems very liquidy, give it 15 more minutes and check it again.
Once the cheesecake has only a slight jiggle, turn the oven off but leave the cheesecake in the oven for another hour or so, until the oven has cooled down. Resist the temptation to open the oven during this time! The purpose of this step is to allow the cheesecake to cool slowly as the oven cools. Doing this will prevent it from cracking, as one of the biggest reasons cheesecakes crack is the drastic temperature change going from the hot oven into the much cooler kitchen.
Once the oven and the cheesecake are cooled, remove from the oven and carefully remove the foil lining the pan. Cover and chill in the fridge for at least 6 hours.
Before serving, whip together the cream, powdered sugar, and zest until medium soft peaks form. Either pipe or spread the whipped cream over the top of the cheesecake and garnish with slices of fresh key limes.