Make the pudding: Whisk the eggs yolks, sugar, cornstarch, and salt together in a medium size saucepan, off of the heat. Whisk in the 2 c whole milk, and place over medium heat. Whisking constantly, bring up to a full boil, and boil for about 3 minutes until the pudding thickens, and starts to pull away from the sides of the pan. Remove from heat immediately, and add the vanilla extract and 2 T salted butter to the pan, and whisk to combine thoroughly. Pour the pudding into a large bowl, and lay a sheet of plastic wrap onto the surface of the pudding (this prevents a layer of pudding skin from forming). Set aside to cool.

Make the whipped cream: Pour the cold heavy cream, sugar, and vanilla extract into a medium sized bowl (or the bowl of a stand mixer). With the whisk attachment of the mixer, or a handheld mixer, beat the cream on medium speed for about 7-8 minutes until medium peaks form. This means that when you stop the mixer and lift the whisk out, the whipped cream creates little peaks that hold their shape. 

Spoon 1/2 c of the whipped cream into the cooled vanilla pudding and fold in with a rubber spatula to loosen up the pudding. Then pour the remaining whipped cream into the lightened up pudding, and gently fold in completely.

Assembling: In a 9-inch square glass baking dish, quickly dunk each biscuit into the milk for 2 seconds, then layer the Petit Beurre biscuits in a single layer, covering the bottom of the pan. Add a layer of about a 2/3 c of the vanilla cream mixture, leveling it out flat with a spatula. Continue with the milk-dunked biscuits, pudding, etc, until all of the vanilla cream mixture is used up. End with a layer of biscuits on top.  Cover with plastic wrap, and chill while you make the chocolate ganache.

Make the chocolate ganache: Chop the chocolate finely, and place in a medium sized heatproof bowl. Heat the 3/4 c heavy in a small saucepan over medium heat, until small bubbles begin to form around the edge of the pan. Pour the hot cream over the chopped chocolate, and let it stand for 1-2 minutes (don't whisk it yet). Then, slowly whisk the chocolate and cream together. The chocolate should melt right into the cream, creating a shiny, smooth ganache. Pour the chocolate ganache over the top layer of the cake. Use a rubber or offset spatula to create a smooth, even finish over top. Top with sprinkles, chopped roasted nuts, or fresh berries. Refrigerate for at least 3 hours before serving. Enjoy!!!