Portobello mushroom burgers are a proven hit with vegans, vegetarians and omnivores alike! These juicy sandwiches are made with hearty mushroom caps slathered in a zippy Dijon mustard sauce. Cook them up in the oven or on the grill!

So, it's August, which means it's late summer, and the perfect time for one of those recipes that gives you the option of cooking with the oven or the grill. Okay, maybe grilling is ideal for this time of year, but I'm a little excited about fall and the prospect of firing up the oven. You can make up your own mind though!
Either way, you should make these portobello burgers.
Also, I should mention that even if you don't have a grill/choose not to grill them, they are so incredibly easy that you totally won't break a sweat during preparation and therefore won't mind the little bit of extra heat in your home at all.
What I really like a about roasting, and what drives me to continue to do it through the summer months is probably the fact that I can toss something together super quick, stick it in the oven, and then walk away. Twenty, thirty, forty minutes go by, I don't even remember I did anything, and then the buzzer reminds me of my awaiting meal. Super easy!
Ingredients You'll Need
- Portobello mushroom caps. Choose large, sturdy caps that look really fresh. Keep in mind that they will shrink when you cook them, so don't worry too much if they appear too large for burger buns.
- Whole grain Dijon mustard. The key to this recipe is the mustard. Pick a really good one! I'm a big fan of Trader Joe's whole grain Dijon mustard. If you have another favorite Dijon mustard, by all means, use it, but please don't go out to the supermarket and pick up any junky old generic Dijon for this recipe. It just won't be the same.
- Olive oil.
- White wine vinegar. Red wine vinegar or even plain old white vinegar will do if that's what you have on hand.
- Maple syrup.
- Garlic.
- Salt & pepper.
- Burger buns. Feel free to use fancy buns if you'd like! A nice ciabatta bun would work really well.
- Toppings. These are truly delicious on their own, but I do love a good burger with toppings piled high, so go for it if you do too. Try lettuce or other greens, sliced tomato, onion, vegan mayonnaise, sprouts, or even sliced vegan cheese.
How They're Made
The following is a detailed photo tutorial on how to make this dish. Scroll all the way down if you'd like to skip right to the recipe!
To make your sauce, whisk Dijon mustard together with minced garlic, white wine vinegar, olive oil and a touch of maple syrup.
Clean up your mushrooms, remove the stems, and use a spoon to scrape out the gills.
Tip: Some folks like to leave the gills in their portobello mushrooms, and you can if you'd like. I prefer to remove them because they can get when cooked.
Brush your mushrooms with the sauce. You'll probably have some extra sauce. Hang on to it!
Stuff the mushrooms into buns and pile on your toppings of choice. Your portobello mushroom burgers are ready to serve!
Leftovers & Storage
Leftover portobello mushrooms can be stored in an airtight container in the fridge for about 3 days.
More Portobello Mushroom Recipes
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Maple Dijon Portobello Mushroom Burgers
Portobello mushroom burgers are a proven hit with vegans, vegetarians and omnivores alike! These juicy sandwiches are made with hearty mushroom caps slathered in a zippy Dijon mustard sauce. Cook them up in the oven or on the grill!
Ingredients
- 4 large portobello caps
- 1 ½ tablespoons whole grain Dijon mustard, plus more for serving, if you like
- 2 tablespoons olive oil
- 1 tablespoon white wine vinegar
- 1 tablespoon maple syrup
- 1 garlic clove, minced
- Salt and pepper to taste
- 4 burger buns
- Toppings of choice
Instructions
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Clean the mushrooms and remove the stems. Scrape out the gills with a spoon.
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Whisk the Dijon mustard, olive oil, vinegar, maple syrup and garlic together in a small bowl. Taste-test and adjust any seasonings to your liking.
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Brush the Dijon mixture all over the outsides of the mushroom caps. Reserve any extra.
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To bake: Preheat the oven to 400°. Arrange the mushrooms on a baking sheet, stem sides up, and bake for 10-12 minutes, until tender.
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To grill: Lightly oil your grill and build a medium flame. Place the mushrooms directly on the grill and cook for about 4 minutes on each side, until slightly charred and tender.
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Remove the mushrooms from the oven or grill and allow them to cool for a few minutes. Sprinkle with salt and pepper to taste.
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Stuff the mushrooms into buns and top with any reserved sauce or additional Dijon mustard and toppings of choice. Serve.
Ive seen other recipes where you're supposed scrape out the gills on the mushrooms. I always leave them in. Is there a specific reason you take them out? Im just wondering.
PS- The photos are beautiful. I love how the green pops! Makes my mouth water. :D
It's not totally necessary, but they can get a little slimy during cooking. Sometimes I leave them in, but since I was using them in a sandwich here I opted to take them out to avoid discoloring or sogging up the bun.
On the photos - thanks so much! I was really happy with how they turned out for this post :)
Is there a substitute for the oil that you recommend?
I think your best bet would be to just leave it out. :)
I made these last night and they were amazing! Really the best marinade recipe I've ever made for these burgers. If I can find smaller caps, they would make wonderful sliders!Thank you for sharing! Wish I would have had your vegan potato salad to go with them! Next time....
Yay!! I'm so glad you enjoyed them! Thanks Suzanne!