Top Dog Hot Dog opened near the UC Berkeley campus in 1966 and has remained a student staple since then. Owner Dick Reimann (a New York native) knows that a good sausage is a meal in itself and doesn't need anything except a top-quality bun. We spiced up this New York-style frank with sauerkraut and the student favorite, Russian spicy mustard, a very spicy and slightly sweet mustard.
Preheat the oven to 300 degrees F.
Put the bread in the oven to warm while cooking the franks. Heat a large griddle or nonstick skillet over medium heat and add the butter. When melted, add the franks and cook, turning, until hot through and browned on the outside, about 5 minutes.
To assemble, put a frank inside a warm piece of bread and drizzle with the sweet hot mustard to taste. Top with sauerkraut.