Preheat oven to 325°F.
Add the graham crackers, brown sugar, and hazelnuts to a food processor, process until well combined. While the food processor is running, add the melted butter, process until combined.
Starting with the sides press well into the bottom of a 9-inch springform or pie pan. Press well using the bottom of a heavy glass or measuring cup.
Add all the ingredients for the chocolate layer into a microwave-safe bowl. Microwave on high for 30 seconds, stir and repeat until melted and combined (alternately, this can be done in the top of a double boiler).
Pour into the crust in an even layer. Refrigerate until set, about 15 minutes.
Make the vanilla layer: Add the cream, beer, and vanilla to a pot over medium heat. Heat until bubbles start to form at the edges and just starting to simmer.
In a large bowl whisk together the egg yolks, sugar, and salt until well combined. While whisking, slowly add the cream mixture until well combined with the yolks (don’t add the hot cream too quickly or it will turn into scrambled eggs).
Add the mixture back into the pot, bring to a simmer, stirring constantly until thickened, about 10 minutes.
Pour over the chocolate layer in an even layer. Bake at 325°F for 35 minutes or until the edges have started to puff, the pie will still be very jiggly. Refrigerate until set, at least 3 hours. Pie is best made the day before.
Add all the whipped cream ingredients to the bowl of a stand mixer, mix on high until soft peaks form, add to the pie in an even layer. Refrigerate until ready to serve.