Prepare the Crust : Preheat the oven to 325°F (165°C). In a mixing bowl, combine graham cracker crumbs, melted butter, and granulated sugar. Mix until evenly moistened. Press the mixture firmly into the bottom of a 9-inch springform pan. Use a flat-bottomed glass to smooth the surface. Bake the crust for 10 minutes. Remove from the oven and let it cool completely.

Make the Cheesecake Filling : In a large mixing bowl, beat the softened cream cheese and sugar until smooth and creamy. Add vanilla extract, lemon juice, and heavy cream. Beat until fully incorporated and fluffy. Purée 1½ mangoes in a blender until smooth. Gently fold the mango purée into the cream cheese mixture.

Prepare the Gelatin : In a small saucepan, combine unflavored gelatin and water. Let it sit for 5 minutes to bloom. Heat over low heat until the gelatin dissolves completely. Allow it to cool slightly, then fold it into the mango cheesecake mixture.

Assemble and Chill : Pour the cheesecake filling over the cooled crust, smoothing the top with a spatula. Sprinkle the remaining diced mango over the top of the cheesecake for a vibrant finish. Refrigerate the cheesecake for at least 6 hours, or until fully set (overnight is best).

Garnish and Serve : Once set, carefully remove the cheesecake from the springform pan. Garnish with fresh mango slices or mint leaves, if desired. Slice and serve chilled, enjoying the tropical flavors in every bite.