1-First Step: Line the pan and make the crust. Start by lining an 8×8-inch square baking pan with parchment paper and coating it with cooking spray. This helps the bars release cleanly later. Place 6 ounces of vanilla wafer cookies and 2 tablespoons of granulated sugar in a food processor and pulse until fine crumbs form. If you do not have a food processor, place the cookies in a sealed bag and crush them with a rolling pin, then mix in the sugar. Drizzle in 6 tablespoons of melted unsalted butter and pulse until the crumbs are evenly moistened. The mixture should hold together when pressed. Transfer it to the prepared pan and press into an even layer using the bottom of a measuring cup or glass. Freeze the crust for 15 minutes so it firms up before the filling goes on top.

2-Second Step: Make the pudding filling. In a medium bowl, whisk together 2 boxes of vanilla instant pudding mix and 2.5 cups of cold heavy cream until the mixture is smooth and thickened. This step moves fast, so keep whisking until you do not see any dry pudding streaks. The filling should look creamy and spreadable. Spread the pudding mixture over the chilled crust in an even layer. Use an offset spatula or the back of a spoon to smooth the top. Then refrigerate the pan for at least 10 minutes. That short chill helps the filling set enough to support the ganache.

3-Third Step: Make the chocolate ganache. Place 6 ounces of chopped semi-sweet chocolate, or 1 cup of semi-sweet chocolate chips, in a heatproof bowl. In a small saucepan, bring 2/3 cup of cold heavy cream to a simmer. Once you see tiny bubbles around the edge, remove it from the heat and pour it over the chocolate. Let the mixture sit for 1 minute so the hot cream can soften the chocolate. Then whisk until smooth and glossy. Let the ganache cool for 3 to 5 minutes. If you want a smooth finish, cool it for about 3 minutes. If you want a swooping pattern on top, cool it closer to 5 minutes so it thickens a bit more.

4-Fourth Step: Add the ganache and chill. Pour the slightly cooled ganache over the pudding layer and spread it carefully to the edges. Try not to press too hard, since the custard layer is soft. Tap the pan lightly on the counter once or twice to help level the top. Refrigerate the bars for at least 2 hours, or until the top is fully set. This long chill is what gives the bars their neat slices and layered look. If you are making them for a party, you can chill them overnight and slice them just before serving.

5-Final Step: Slice and serve. Lift the slab out of the pan using the parchment paper. Set it on a cutting board and cut it into 12 to 16 pieces, depending on how large you want each bar to be. Wipe the knife clean between cuts so the layers stay sharp and neat. A cloth works well for quick cleanup between slices.