Preparation Steps

• Line a 9×13-inch pan with a parchment sling for easy lifting. Count out about 27 graham cracker sheets and set aside; break a few to patch gaps if needed.
• Make the chocolate topping first so it can cool: Place chopped chocolate, butter, and a pinch of salt in a medium heatproof bowl. Microwave the cream until steaming (45–60 seconds), then pour over the chocolate. Let sit 2 minutes, then stir from the center outward until smooth and glossy. Set aside at room temperature 25–30 minutes to thicken to a spreadable consistency.
• Whisk the pudding mixes with the cold milk for about 1 minute until smooth. Refrigerate for 5 minutes to lightly set.
• In a separate bowl, whip the cold heavy cream with the powdered sugar on medium-high speed until medium peaks form—creamy and billowy, not stiff (about 2–3 minutes).
• Stir the vanilla extract into the chilled pudding. Fold in the whipped cream in two additions with a spatula until no streaks remain; avoid overmixing to keep it airy.
• Assembly—Layer 1: Swipe a spoonful of filling over the bottom of the pan to anchor. Arrange a tight, even layer of graham crackers on top, patching corners as needed.
• Spread half of the vanilla cream over the crackers all the way to the edges. Tap the pan gently to settle the layer, then add a second even layer of crackers.
• Add the remaining vanilla cream, smooth, and finish with a final cracker layer, pressing lightly so everything makes contact. Cover and refrigerate 30 minutes to firm before topping.
• Top with chocolate: If the ganache has thickened to a pourable-but-spreadable state, spoon it over the surface and smooth with an offset spatula. If it seems too thick, warm it in 5-second microwave bursts, stirring between each, until fluid.
• Cover the pan and chill at least 6 hours, preferably overnight, so the crackers soften into cake-like layers. Slice with a knife warmed under hot water and wiped dry between cuts.