Line a 9x13-inch baking pan with parchment paper, leaving an overhang on two sides for easy lifting.

In a medium bowl, combine the graham cracker crumbs and 1/3 cup granulated sugar. Pour in the melted butter and stir until all crumbs are evenly moistened and hold together when pressed.

Tip the crumb mixture into the prepared pan and press it firmly into an even layer using the bottom of a measuring cup or glass. Chill the crust in the refrigerator while you prepare the filling.

If using gelatin, sprinkle the gelatin over 2 tablespoons of cold water in a small bowl and let it bloom for 5 minutes. Once bloomed, gently warm it in the microwave in short bursts or over a pan of hot water until just melted and fluid. Let cool slightly but do not let it set.

In a large mixing bowl, beat the cold cream cheese with an electric mixer until completely smooth and free of lumps, scraping down the sides of the bowl as needed.

Add the powdered sugar and vanilla extract to the cream cheese and beat until smooth and creamy. Mix in the Greek yogurt or sour cream until fully combined.

In a separate bowl, whip the cold heavy cream to soft peaks with an electric mixer.

If using gelatin, whisk a spoonful of the cream cheese mixture into the melted gelatin to temper it, then beat this mixture back into the main cream cheese bowl until evenly incorporated.

Gently fold the whipped cream into the cream cheese mixture in two to three additions, using a spatula and broad, gentle strokes to keep the mixture light and airy.

Fold in 1 1/2 cups of the chopped mini chocolate Easter eggs until just distributed.

Pour the cheesecake filling over the chilled crust and spread it into an even layer, smoothing the top with an offset spatula.

Gently press some of the whole or halved mini eggs into the surface so they anchor in the soft filling, reserving a handful for serving.

Cover the pan tightly with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, until the center feels set and slightly springy when gently pressed.

When ready to serve, scatter the remaining mini eggs over the top for fresh color and crunch.

Lift the bars out of the pan using the parchment overhang. Run a thin, sharp knife under hot water, wipe it dry, and cut the slab into 16 squares, warming and wiping the knife between cuts for the cleanest slices.