Crush the graham crackers into fine crumbs using a food processor or by placing them in a zip-top bag and crushing with a rolling pin. Transfer the crumbs to a bowl.
Pour the melted butter over the crumbs and stir until evenly coated. Press this mixture firmly into the base of a springform pan, creating a smooth, even layer. Chill in the fridge for about 15 minutes to set.
Peel and chop the mangoes, then blend them until you have about 1 1/2 cups of smooth mango puree. Set aside.
Sprinkle the gelatin powder over the cold water in a small bowl and let it bloom for 5 minutes. Once bloomed, gently heat the mixture in a small saucepan over low heat, stirring until the gelatin completely dissolves and becomes clear. Avoid boiling.
In a mixing bowl, beat the softened cream cheese until smooth and creamy. Add the mango puree, honey or sugar if using, and the dissolved gelatin. Mix until fully combined and the mixture is smooth and glossy.
Pour the mango filling over the chilled crust, spreading it evenly with a spatula. Cover loosely with plastic wrap and refrigerate for at least 4 hours, or overnight, until set and firm.
Once set, run a hot, damp knife around the edges of the springform pan to loosen the cheesecake. Carefully remove the sides of the pan.
Decorate the top with thin slices of mango or mint leaves for a beautiful finish. Let sit at room temperature for 10 minutes before slicing.
Slice with a hot, damp knife for clean cuts and serve immediately. Enjoy the vibrant, tropical flavors and glossy finish of this no-bake mango cheesecake!
