In the same pot you boiled the pasta, cook the bacon over medium heat until browned and crisp. Remove the bacon from the pot and drain on a paper towel lined plate. Drain all but one tablespoon of the bacon grease out of the pot. In the same pot, melt the 4 tablespoons butter over medium heat. Whisk in the flour. Reduce the heat to medium-low and let cook/bubble for 1 minute, stirring once or twice to avoid burning. Gradually whisk in the beer and cook another minute. Now slowly pour in the milk, whisking until combined. Raise the heat up to medium-high. Bring the mixture to a boil, whisking frequently until the sauce has thickened, about 2-3 minutes. Remove from the heat and stir in all of the cheese, kale pesto, mustard powder, cayenne, salt and pepper. Stir until the cheese is fully melted (if needed, return the pot to the heat to fully melt the cheese). Stir in the pasta and bacon, transfer to the prepared baking dish. Sprinkle on the potato chips crumbs and place the baking dish on top of a baking sheet. Bake for 25-30 minutes or until the crumbs are golden brown and the sauce is bubbling. Remove from the oven and let site five minutes (yeah, right). Top with the kale pesto slaw. Dig in!!