Preheat oven to 350.
Add the chips, flour, cornstarch, and brown sugar to a food processor, process until chips have been reduced to crumbs. While the food processor is running, add the melted butter until well combined with the potato chip crumbs.
Starting with the sides, press the crust into a 9-inch tart crust with removable bottom (alternately, you can use a spring form pan, pressing the sides up just about 1 ½ inches).
Bake at 350 for 10-12 minutes, or until crust is golden brown. Remove from oven and allow to cool.
In a microwave safe bowl add the chocolate chips and ½ cup porter. Microwave for 45 seconds, stir and repeat until melted. Allow to cool for ten minutes.
In the bowl of a stand mixer add the cream, remaining 2 tablespoons porter, salt and powdered sugar. Beat on high until soft peaks form.
While mixer is running, slowly add the chocolate until well combined.
Spoon into cooled crust in an even layer. Refrigerate until ready to serve.