Combine graham cracker crumbs and sugar in a medium bowl. Stir in melted butter until mixture resembles wet sand.

Press firmly into the bottom of a 9-inch springform pan. Use the bottom of a measuring cup to compact the crust evenly.

Chill in the fridge while you prepare the filling — 10–15 minutes will do.

Sprinkle gelatin over 3 tablespoons cold water and let sit for 5 minutes. If you’re using powdered gelatin, follow the packet’s instructions for blooming.

Microwave the bloomed gelatin for 10–15 seconds until dissolved (don’t boil). Set aside to cool slightly.

In a large bowl, beat the softened cream cheese and powdered sugar until smooth and lump-free (about 2–3 minutes).

Add the sweetened condensed milk, lime zest, and lime juice. Beat on low until combined and creamy.

In a separate bowl, whip the cold heavy cream to soft peaks.

Stir a couple of tablespoons of whipped cream into the cream cheese mixture to lighten it.

Gently fold in the remaining whipped cream until mostly combined; don’t overmix.

Slowly drizzle in the dissolved gelatin while folding — this helps the mousse set without lumps.

Pour filling over the chilled crust and spread evenly. Smooth the top with a spatula.

Cover and chill the cheesecake for at least 4 hours, preferably overnight. This allows the mousse to set firm and the flavors to meld.

In a small saucepan, combine sugar, water, and lime juice. Warm gently until sugar dissolves.

Stir in the cornstarch slurry and cook until slightly thickened, 1–2 minutes. If using gelatin, add the bloomed gelatin now and stir to dissolve.

Remove from heat and cool to room temperature. If desired, add a drop or two of green food coloring for an extra glossy finish.

Carefully pour glaze over the chilled cheesecake and spread evenly. Return to fridge for 15–30 minutes to set the glaze.

Release the springform ring and transfer to a serving plate.

Garnish with lime slices, extra zest, and whipped cream dollops.

Slice with a sharp knife dipped in hot water for clean cuts.