French Dip on Sourdough | Roast Beef Sandwich Recipe

🥪 Ingredients

• 4 thick slices sourdough bread
• 10 ounces thinly sliced roast beef
• 4 slices provolone cheese
• 1 large yellow onion, thinly sliced
• 1 tablespoon butter
• 1 teaspoon olive oil
• 2 cups beef broth
• 1 tablespoon Worcestershire sauce
• 1 teaspoon soy sauce
• 1/2 teaspoon garlic powder
• 1/2 teaspoon dried thyme
• 1/4 teaspoon freshly ground black pepper
• 1 teaspoon Dijon mustard, optional
• 1 tablespoon softened butter or olive oil for toasting the bread

🔥 How to Make It

1. Caramelize the onions.
   Melt the butter with the olive oil in a skillet over medium-low heat. Add the sliced onion and cook for about 18–20 minutes, stirring occasionally, until soft, golden, and sweet.
2. Make the au jus.
   In a saucepan, combine the beef broth, Worcestershire sauce, soy sauce, garlic powder, thyme, and black pepper. Bring to a gentle simmer and cook for 5–7 minutes so the flavors come together.
3. Warm the roast beef.
   Reduce the au jus to low heat and add the sliced roast beef for about 1–2 minutes, just until warmed through. Do not boil it into submission.
4. Toast the sourdough.
   Lightly butter or brush the bread with olive oil and toast until golden and crisp around the edges.
5. Build the sandwiches.
   Spread Dijon on two slices of sourdough if using. Layer on the warm roast beef, caramelized onions, and provolone.
6. Melt the cheese.
   Place the open sandwiches under the broiler briefly, or cover them in a skillet over low heat, until the provolone is soft and melty.
7. Close and slice.
   Top with the remaining sourdough slices, press gently, and cut each sandwich in half.
8. Serve with au jus.
   Divide the warm au jus between small bowls and serve alongside the sandwiches for dipping. Dunk enthusiastically, but not long enough to lose structural integrity.