Preheat a griddle or large cast-iron skillet over medium-high heat. Place the beef in a bowl and season with the Worcestershire, salt (for a crusty coating on the burgers) and pepper. Using a box or hand-held grater, grate 3 to 4 tablespoons of the peeled onion over the meat (the grated onion and its juice will flavor the meat itself, plus keep the burgers moist as you cook them). Add the parsley. Mix the meat, but do not overwork it. Form 6 patties, thinner at the center than at the edges for even cooking. Drizzle with EVOO. Cook the burgers, turning once, for 6- 8 minutes for pink centers.
Serve the burgers on the bun bottoms and top with the sour cream sauce, potato chips, a couple of pickles each and the bun tops.
Sierra Nevada Stout: The roasty, bold flavors of this classic American stout match the rich beef and creamy dip.