Classic Roast Beef Sandwich with Homemade Au Jus and Caramelized Onions

How to Make Classic Roast Beef Sandwich with Homemade Au Jus and Caramelized Onions

1. 1

   Step 1: Caramelize the onions

   Heat butter and olive oil in a large skillet over medium-low heat. Add the thinly sliced onions and a pinch of salt, then cook gently, stirring every few minutes, until deep golden and sweet, about 25–30 minutes; adjust heat to prevent burning.

   For this step

   • 2 mediumYellow onions, thinly sliced
   • 2 tbspUnsalted butter
   • 1 tbspOlive oil
   
2. 2

   Step 2: Make the au jus and warm the beef

   In a small saucepan, add red wine and simmer 1–2 minutes to reduce slightly, then add beef broth and Worcestershire sauce and simmer 5–7 minutes to marry the flavors. Add the sliced roast beef to the simmering au jus just to warm through (30–60 seconds) so it stays tender; keep the au jus hot for serving.

   For this step

   • 12 ozLeftover roast beef, thinly sliced
   • 2 cupsBeef broth (low-sodium preferred)
   • 1/4 cupDry red wine (or additional beef broth)
   • 1 tbspWorcestershire sauce
   
3. 3

   Step 3: Prepare and toast the rolls

   Preheat broiler or oven to 375°F (190°C). Split the rolls and place cut-side up on a baking sheet; toast in the oven or under the broiler for 2–4 minutes until lightly golden. Remove and keep warm.

   For this step

   • 4 rollsSandwich rolls (kaiser or French), split
   
4. 4

   Step 4: Assemble and melt the sandwiches

   Pile warmed roast beef on the bottom halves of toasted rolls, top with a generous spoonful of caramelized onions and a slice of provolone. Return sandwiches to the oven or place under the broiler for 1–2 minutes until the cheese melts and edges are bubbly.

   For this step

   • 4 slicesProvolone cheese slices
   
5. 5

   Step 5: Serve with au jus for dipping

   Transfer the au jus to small individual dipping bowls and serve alongside the assembled sandwiches so each person can dip as desired. Enjoy immediately while hot for the best texture and flavor.
   

1. Heat butter and olive oil in a large skillet over medium-low heat. Add the thinly sliced onions and a pinch of salt, then cook gently, stirring every few minutes, until deep golden and sweet, about 25–30 minutes; adjust heat to prevent burning.
2. In a small saucepan, add red wine and simmer 1–2 minutes to reduce slightly, then add beef broth and Worcestershire sauce and simmer 5–7 minutes to marry the flavors. Add the sliced roast beef to the simmering au jus just to warm through (30–60 seconds) so it stays tender; keep the au jus hot for serving.
3. Preheat broiler or oven to 375°F (190°C). Split the rolls and place cut-side up on a baking sheet; toast in the oven or under the broiler for 2–4 minutes until lightly golden. Remove and keep warm.
4. Pile warmed roast beef on the bottom halves of toasted rolls, top with a generous spoonful of caramelized onions and a slice of provolone. Return sandwiches to the oven or place under the broiler for 1–2 minutes until the cheese melts and edges are bubbly.
5. Transfer the au jus to small individual dipping bowls and serve alongside the assembled sandwiches so each person can dip as desired. Enjoy immediately while hot for the best texture and flavor.