These mushroom French dip sandwiches are the perfect vegetarian twist on a classic recipe! Loaded with caramelized onions, tender mushrooms, and provolone cheese, these sandwiches are served with a rich, flavorful broth for dipping.

Mushroom Sandwich
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I wanted to make a meatless version of a French dip sandwich that is just as satisfying as the original. Mushrooms are the perfect swap because they have a hearty texture and soak up all the delicious flavors from the broth. Pair this sandwich with a side of roasted cauliflower or a simple kale salad, and dinner is ready in about 30 minutes!

Ingredients & Substitutions

  • Olive oil – This helps soften the onions and adds richness. You can use any kind of neutral oil.
  • Yellow onion – Caramelized onions bring sweetness and depth. You can substitute with a white onion or shallots.
  • Garlic & thyme – A little fresh garlic and dried thyme help build flavor.
  • Portobello & shiitake mushrooms – This blend of mushrooms adds a meaty texture and earthy flavor.
  • Dijon mustard – A little mustard adds a tangy complexity.
  • Tomato paste – This adds an umami flavor and helps add depth to the broth.
  • Sherry or dry white wine – A splash of sherry or white wine also helps build flavor. You can substitute with vegetable broth and a splash of white wine vinegar, if you don’t have wine.
  • Vegetable stock – Creates the rich dipping broth. I used a vegan beef-style broth, but you can use whatever kind you have on hand.
  • Provolone cheese – A French dip sandwich is traditionally topped with provolone or Swiss. I used Provalone, but you can use either one!
  • Hoagie buns – A hearty, crust bread is the best for soaking up the juices.
  • Mayonnaise – You can skip this if you don’t want to use mayonnaise, but it adds richness to the sandwich.

How to Make a Mushroom French Dip Sandwich

Add the olive oil and onion to a large skillet and cook over low heat for 8-10 minutes until the onions soften and begin to brown.
Add the portobello mushrooms and shiitake and 1/4 teaspoon salt and cook over medium heat for 5-6 minutes until tender. 
Add the garlic and continue to cook for one minute, then add the mustard, tomato paste, and thyme.
Continue to cook over medium heat for one minute, then add the sherry, scraping up any browned bits from the bottom of the pan.
Add the vegetable stock and bring to a simmer. Simmer, uncovered, for 5 minutes, then season with salt, if needed
Toast the buns, then divide the mushroom and onion mixture onto the bottom buns of the hoagie buns.
Top the mushroom mixture with a slice of provolone cheese and place the sandwich back in the oven for one minute to melt the cheese.
Once out of the oven, top each of the hoagie buns with mayonnaise, if desired.
Mushroom Sandwich
Enjoy!

Tips for Perfect French Dip Sandwiches

  • Use a mix of mushrooms for the best texture and flavor.
  • Don’t skip toasting the bun. Toasting it keeps the bread from getting soggy.
  • This sandwich is best served immediately, so enjoy it right away.

What to Serve with Mushroom Sandwiches

These sandwiches are filling on their own, but they’re also great paired with skillet green beans, Brussels sprout salad, or roasted broccoli salad.

mushroom sandwich

Storage & Reheating

If you have leftovers, store the mushroom filling and broth separately from the bread to prevent sogginess. Reheat the filling in a skillet over medium heat until warmed through. Toast the bun, then top with the mushroom mixture and cheese.

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Mushroom Sandwich

Mushroom French Dip Sandwich

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  • Author: Liz Thomson
  • Prep Time: 10 minutes
  • Cook Time: 25 minutes
  • Total Time: 35 minutes
  • Yield: 4 sandwiches 1x
  • Category: Dinner
  • Method: Stovetop and Oven
  • Cuisine: American
  • Diet: Vegetarian
Print Recipe

Description

These mushroom French dip sandwiches are the perfect vegetarian twist on a classic recipe! Loaded with caramelized onions, tender mushrooms, and provolone cheese, these sandwiches are served with a rich, flavorful broth for dipping.

Ingredients

Units Scale
  • 2 teaspoons olive oil
  • 1 small yellow onion, thinly sliced
  • 1 clove garlic, minced
  • 2 large portobello mushrooms, gills removed, sliced into thin strips
  • 5oz shitake mushrooms, sliced
  • 1/4 teaspoon salt, divided
  • 2 teaspoons Dijon mustard
  • 1 tablespoon tomato paste
  • 1 teaspoon thyme
  • 1/4 cup sherry or dry white wine (I used cooking wine)
  • 1/2 teaspoon black pepper
  • 1 cup vegetable stock
  • 4 slices Provolone cheese
  • 2 tablespoons mayonnaise (optional)
  • 4 Hoagie buns

Instructions

  1. Preheat the oven to broil.
  2. Add the olive oil and onion to a large skillet and cook over low heat for 8-10 minutes until the onions soften and begin to brown.
  3. Add the portobello mushrooms and shiitake and 1/4 teaspoon salt and cook over medium heat for 5-6 minutes until tender.
  4. Add the garlic and continue to cook for one minute, then add the mustard, tomato paste, and thyme.
  5. Continue to cook over medium heat for one minute, then add the sherry, scraping up any browned bits from the bottom of the pan.
  6. Add the vegetable stock and bring to a simmer. Simmer, uncovered, for 5 minutes, then season with pepper and salt, if needed
  7. Cut the hoagie buns in half and toast in the oven on the broil setting for 1-2 minutes until golden brown.
  8. Divide the mushroom and onion mixture onto the bottom buns of the hoagie buns using a slotted spoon to drain any liquid.
  9. Top the mushroom mixture with a slice of provolone cheese and place the sandwich back in the oven for one minute to melt the cheese.
  10. Once out of the oven, top each of the hoagie buns with mayonnaise, if desired.

  11. Add the top bun and serve with the reserved liquid to dip the sandwich in.