Line an 8x8-inch square pan with parchment paper, allowing the edges to extend slightly beyond the sides for easy removal after chilling.
In a small saucepan over gentle heat, combine the white chocolate morsels and sweetened condensed milk. Stir consistently until the mixture becomes fully melted and silky smooth.
Add the softened cream cheese and vanilla essence into the warm chocolate mixture. Mix thoroughly using a whisk or spatula until the blend is homogenous and free of any lumps.
Transfer the mixture into the parchment-lined dish, spreading it evenly across the surface. If desired, scatter the crushed graham crackers over the top or gently swirl them into the surface.
Place the dish in the refrigerator and allow it to set for 3 to 4 hours, or until the texture is firm enough to slice cleanly.
Once set, lift the fudge out of the pan using the parchment overhang, cut into even squares, and serve.