It's the salty kummelweck roll that makes this sandwich unique. Made only in the Buffalo-Rochester area, the kummelweck is basically a Kaiser roll topped with lots of pretzel salt and caraway seeds.
8 kummelweck rolls (see note), split
8, 6-oz. portions thinly sliced rare roast beef
4 oz. prepared horseradish sauce or grated horseradish, or to taste
2 cups prepared au jus or roast beef drippings
Note: Kummelweck rolls are salted caraway rolls. If unavailable, brush a mixture of cornstarch and water on the tops of Kaiser rolls and sprinkle with equal amounts of pretzel salt and caraway seed. Heat in a 350°F oven until crisp, about 3 min.
1. Toast rolls lightly and place 6 oz. roast beef on the bottom of each. Spread beef with horseradish sauce or horseradish.
2. Brush top half of each roll generously with au jus and serve immediately, with additional au jus on the side.