These vegan French dip sandwiches are made with sautéed portobellos, dressed in spicy horseradish mustard and served ready for dipping in savory vegan au jus.
Roast beef has never been my thing. I know, you're shocked! So the idea of a French dip sandwich never appealed to me very much. In fact, I distinctly remember ordering a French dip at Denny's when I was a little kid, and thinking I'd be getting something involving French onion dip, which definitely was my thing. I was hugely disappointed when a roast beef sandwich with a cup of meat juice showed up.
A big messy mushroom sandwich that gets dunked in mushroom juice on the other hand, is way my cup of tea.
I'm really glad I got over that rough childhood French dip experience, and decided to give it another go, in vegan form, because this sandwich was insane! Flavorful, succulent, sloppy as heck, but so worth the slop for being as tasty as it was.
I served my sandwiches with some horseradish mustard and nothing more. That was perfect for me, but I've seen recipes calling for spicy mustard, Dijon and mayo. Go with them all if you'd like, assuming you're prepared for a full-on slop fest. If you're into vegan cheese, feel free to top it all off with some mozzarella shreds too.
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Vegan French Dip Sandwiches
- 2 tbsp. olive oil, divided
- 1 medium onion sliced into half rings
- 2 garlic cloves minced
- 3 portobello mushroom caps, about 20 oz. total, cleaned and sliced into thin strips
- 1 cup vegetable broth
- 1 tbsp. soy sauce
- 1 tbsp. vegan Worcestershire sauce
- ½ tsp. dried thyme
- ¼ tsp. liquid smoke, optional, but highly recommended
- ¼ tsp. black pepper
- 2-6 inch sandwich rolls or baguette sections sliced open
- horseradish mustard
Coat the bottom of a large skillet with 1 tablespoon of oil and place over medium-low heat. Add onion and toss a few times to coat with oil. Allow to cook until caramelized, about 20 minutes, flipping occasionally. Add garlic and cook about 2 minutes more. Transfer onions and garlic to a plate.
Coat skillet with another tablespoon of oil and raise heat to medium. Add mushroom strips. Avoid overcrowding the skillet. A little overlapping is okay, but work in multiple batches if needed (I needed two), adding a bit of oil between batches if needed. Cook until lightly browned, about 5 minutes. Flip and cook 5 minutes more on opposite sides.
Return onions to skillet and add broth, soy sauce, Worchestershire sauce, thyme, liquid smoke and pepper. Bring to a simmer and allow to cook, stirring occasionally, until liquid is reduced by half, about 5 minutes.
Slather the insides of rolls with horseradish mustard. Use a slotted spoon to remove onions and mushrooms from skillet, pressing lightly to squeeze out any excess juice. Divide onions and mushrooms into rolls. Pour cooking liquid into a small bowl and serve with sandwiches, for dipping.