Why It Works
- Cooking the mushrooms in stages and not overcrowding the skillet ensures they brown and develop a rich flavor.
- Tomato paste thickens the sauce, creating a velvety texture.
- Partially toasting the rolls before topping them with the mushroom mixture prevents them from turning too soggy.
For many of my formative years, my family suffered through my dad’s hippie vegetarian phases. Before you judge me too harshly for criticizing my dad’s cooking attempts, consider that this was the ’80s and ’90s, when plant-based diets were not as prevalent in the US as they are today. My dad’s culinary skills were also…limited. Meals were usually a sad mixture of overcooked brown rice, mushy steamed vegetables, and a few scattered cashews. But while those dinners didn’t win me over then, they planted a seed. Years later, after some on-and-off flirtations with vegetarianism, I’ve come to see vegetables not just as sides, but as the heart of a meal.
That’s why I love this vegetarian French dip sandwich. It’s not trying to imitate the original LA classic, with its thinly sliced beef and rich jus. Instead, it’s its own thing—a deeply savory, satisfying sandwich that just happens to be meatless. Mushroom lovers and flexitarian omnivores alike will be into this one.
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How to Build Deeply Savory Flavor Without Meat
The success of this sandwich starts with the right mushrooms—using a combination of mushrooms gives the sandwich complexity in terms of both flavor and texture. Meaty, sliced portobellos are first seared in a hot skillet until deeply browned. After that, you layer in a variety of flavorful mushrooms—cremini, oyster, shiitake, trumpet, even beech if you’ve got them. The key is to work in small batches so the mushrooms sear, rather than steam. Overcrowding = soggy mushrooms, and nobody wants that. Proper browning builds flavor and gives the mushrooms a juicy, chewy bite.
To amp up the depth of flavor and umami punch even more, I add rehydrated dried porcini mushrooms. Soak them in hot water until softened, then chop and set aside. Don’t toss that soaking liquid—it’s liquid gold and becomes the backbone of your jus.
A Rich Vegetarian Jus That Rivals the Original
From here, it’s all about building layers of flavor for the sauce. After the mushrooms are browned, aromatics such as onions, garlic, and fresh thyme are added to the pan. A spoonful of tomato paste adds even more umami and gives the sauce body. Then it’s all about deglazing: I prefer dry vermouth for its herby, slightly citrusy edge, but dry white wine works just as well. Stir in the reserved porcini soaking liquid (this packs lots of flavor) and your favorite vegetable or mushroom broth, and simmer until the sauce thickens slightly.
What you end up with is an intensely savory, velvety jus—perfect for dunking. It’s rich without being heavy, and layered with earthy, herby, almost meaty flavors.
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Tips for Assembling the Perfect Sandwich
The assembly for this sandwich is very similar to a traditional French dip: Use good-quality French or hoagie rolls and toast them lightly before filling. Then pile on the mushroom mixture with tongs or a slotted spoon (you want the filling, not the liquid here). Top with slices of sharp aged provolone or Swiss cheese, then broil until the cheese is melted and bubbling. Serve the remaining jus in small bowls on the side, and you have a sandwich that delivers all the cozy, dip-it-yourself pleasure of the classic—no beef required.
I wish this sandwich had been on the table during those early vegetarian years. It’s hearty, cheesy, and satisfying, with rich flavor and plenty of textural contrast. And while it’s meatless, it doesn’t feel like it’s missing anything. If you’ve been dreaming of a French dip but want to keep it vegetarian—or just want a shroomier version from time to time—this one delivers.
Meet the Meatiest French Dip Sandwich—but Hold the Beef
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3/4 cup (180 ml) hot water
1/2 ounce (14 g) dried porcini mushrooms
3 tablespoons (45 ml) olive oil, divided
2 large portobello mushrooms (about 3 ounces; 85 g each), stems and gills removed, cut into 1/4-inch thick slices
6 ounces (170 g) mixed mushrooms, such as oyster, shiitake, and/or cremini, roughly chopped
1 medium yellow onion (8 ounces; 226 g), diced (1 cup diced)
2 cloves garlic, minced
2 teaspoons minced fresh thyme leaves
1 tablespoon (15 ml) tomato paste
1/4 cup (60 ml) dry vermouth or dry white wine
2 cups (480 ml) homemade or storebought low-sodium vegetable or mushroom broth
3/4 teaspoon Diamond Crystal kosher salt; for table salt, use half as much by volume
1/4 teaspoon freshly ground black pepper
2 (7- to 8-inch long) store-bought or homemade French rolls or hoagie/sub rolls (about 6-ounces each), split lengthwise, but left attached on 1 side to create a hinge
4 thin slices aged provolone or Swiss cheese (about 2 ounces; 56 g total weight)
In a medium bowl, add hot water and dried porcini and set aside until mushrooms are softened, about 10 minutes. Remove mushrooms, using your hands to squeeze excess liquid back into bowl, transfer to cutting board, and roughly chop. Set aside and reserve soaking liquid.
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Meanwhile, in a large stainless steel or cast iron skillet, heat 2 tablespoons oil over medium-high heat until shimmering. Add sliced portobellos in a single layer and cook, undisturbed, until slightly golden brown on bottom, about 4 minutes. Stir, and continue cooking until browned all over, 3 to 4 more minutes.
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Use a wooden spoon to push mushrooms to the perimeter of skillet and add remaining 1 tablespoon oil to center of skillet. Add half of mixed mushrooms to oil and cook, undisturbed, until slightly browned on bottom, about 1 minute. Stir and continue cooking until slightly browned all over, 2 to 3 minutes. Again, push browned mushroom mixture to edge of skillet and repeat with oil and remaining mushrooms.
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Stir all mushrooms together, then add onion, garlic, and thyme and cook, stirring occasionally, until onions start to soften, about 2 minutes. Add tomato paste and stir to combine, then cook until tomato paste is slightly caramelized, about 1 minute, lowering heat if needed to avoid scorching.
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Pour in vermouth and reserved mushroom soaking liquid. Cook until slightly reduced, about 1 minute. Pour in vegetable or mushroom broth and add reserved porcini mushrooms. Sprinkle with salt and pepper and reduce heat to maintain a low simmer. Cook until sauce is slightly thickened and reduced, about 10 minutes.
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Meanwhile, adjust oven rack to upper-middle position and preheat oven broiler to high. Cut open rolls and lay flat, cut-side up, on a baking sheet. Broil until slightly toasted, about 30 seconds.
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To Build Sandwiches: Use tongs or a slotted spoon to divide mushroom mixture evenly among bottom of rolls (reserve the sauce). Top with cheese. Broil until cheese is bubbly and slightly browned, 1 to 2 minutes. Close sandwiches with top halves of rolls. Transfer remaining mushroom jus to individual sauce bowls and serve on the side.
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Special Equipment
Large stainless steel or cast iron skillet, rimmed baking sheet, slotted spoon or tongs
Notes
If you want to double this recipe, cook the mushrooms in two stages and remove them to a mixing bowl to avoid overcrowding the skillet.
Make-Ahead and Storage
The filling and jus can be made ahead and refrigerated in separate airtight containers for up to 4 days. They can be reheated together in a large skillet on the stovetop until heated through.
