If you're getting excited about grilling outdoor dinners, you have to try this vegan main dish! It's Grilled Portobello Mushrooms and Onions made with a simple marinade that adds the most incredible flavor to every bite.
My very favorite meals are ones made outside and enjoyed in the sunshine with the people I love the most. Needless to say, summertime is my favorite time of year, and I get so excited when it's finally time to fire up the grill! Portobello mushrooms are a classic vegan burger replacement, but they're just as good as a main dish if you want to skip the bun. This recipe for Grilled Portobello Mushrooms and Onions is my very favorite dish right now...I can't get enough! The simple marinade really makes it pop and it pairs perfectly with all of my favorite summer side dishes.
Ingredients in Grilled Portobello Mushrooms
The main ingredients here are, of course, mushrooms and onions. I whisked up a quick marinade to add the most delicious, subtle flavor! You can even prep this marinade ahead of time and store it in the refrigerator until you're ready to start grilling.
- Portobello Mushrooms - These mushrooms are so big that I only use four of them for this recipe. You can trim the stems off or just snap them off by hand.
- Red Onion - Use a medium-sized red onion and slice it into ½-inch rings. Try to get the sizes of the rings as uniform as possible so they cook evenly!
- Olive Oil - Just a splash of oil will help all of the marinade ingredients mix together and keep your onions and portobellos from sticking to the grill.
- Maple Syrup - This is my favorite all-natural sweetener! Make sure the only ingredient is pure maple.
- Garlic Cloves - I either mince them very finely or press the cloves through a garlic press. This lets them mix evenly into the marinade so you get garlic in every bite!
- Dijon Mustard - This is an ingredient that I always keep on hand for homemade dressings, sauces, and marinades like this one. It adds the perfect bold flavor!
- Salt and Pepper - The usual finishing touches! You can start with a little and adjust to your preference here.
How to Grill Portobello Mushrooms
Portobello Mushrooms just might be one of the easiest things to make on the grill! I whisk a marinade of olive oil, pressed garlic, Dijon mustard, and a splash of pure maple syrup to brush on each side of the mushrooms and onions. Let it sit for 15 minutes to really let those delicious flavors soak in! Place the marinated veggies directly on the grill over medium heat. Cook for 8 minutes per side with the grill covered until each side has those beautiful, charred grill marks. The mushrooms should be knife tender and juicy.
All About Portobello Mushrooms
I received a Master of Public Health degree as well as a Master Certified Health Education Specialist (MCHES) credential through the NCHEC because I am passionate about evidence-based knowledge of the ways food impacts our bodies. Knowledge is power, and when it comes to nutrition, knowledge is also health! Let's talk about why mushrooms are such a good choice: they are low in calories, high in dietary fiber, and full of riboflavin, a B vitamin that is essential for metabolic health! They are also a good source of niacin, copper and pantothenate. Three ounces of raw mushrooms, about 1 cup, provide 1 to 2 grams of protein as well as an indigestible carbohydrate called chitin that adds “bulk” to our diet. Surprisingly, mushrooms also provide a small amount of vitamin D and they can even increase their vitamin D content when they are exposed to light, just like our skin does! (source) No other “vegetable” can to do that!
I love their savory flavor and hearty texture, which makes a perfect meat substitute during grilling season. I look for firm, well-shaped mushrooms that do not have any spots or slime on them. You can store mushrooms in your refrigerator in their original container (or a paper bag) for up to one week, but like most produce, they are best when fresh. I try to buy them the day before whenever possible.
More mushroom recipes:
How to Enjoy Grilled Portobellos and Mushrooms
Like I mentioned above, I have been craving and enjoying grilled mushrooms since the first time we fired up the grill this summer. They're my favorite food right now! To keep some variety in the menu, here are a couple different ways I would use these:
- The most classic way people enjoy these Grilled Portobello Mushrooms is in a burger as a replacement for a hamburger patty. They're hearty and delicious! Grab your favorite gluten-free bun and layer on tomato, lettuce, red onion, and a few slices of avocado. Summertime in every bite!
- Slice them up and eat them in tacos! They would be delicious on top of my Easy Sheet Pan Veggie Tacos.
- Serve over a bed of Perfectly Cooked Quinoa in the Instant Pot or Easy Coconut Rice with Quick & Easy Creamy Hummus or Easy Creamy Tahini Sauce.
- My very favorite way to enjoy these is on their own! I love eating them alongside my favorite grilled veggies with a drizzle of Chermoula Sauce or Jalapeno Chimichurri.
- Include Grilled Portobello Mushrooms with Grilled Veggie Pesto Pasta...YUM!
Vegan Summer Side Dishes
My summer cooking solution is to avoid turning the oven on whenever possible! I love to prep sides in the morning when it's cooler, then store them in the refrigerator until dinnertime. This works especially well with potato and pasta salads, which taste best after the flavors have combined for a bit! These sides would be perfect to pull out of the fridge while the grill heats up after an afternoon at the pool. My dream day! For more on how I make nutritious, plant-based meals for my family, check out my post on Foods I Meal Prep Every Week.
- Creamy Vegan Picnic Pasta Salad
- Simple Side Salad Recipe
- Vegan Summer Slaw
- Horiatiki: Greek Village Salad with Tomatoes & Cucumber
- Broccoli & Zucchini Vegan Pasta Salad
- Summer Salad with Strawberry Vinaigrette
- Vegan Summer Macaroni Pasta Salad
- Lemon Olive Oil & Dill Potato Salad
- Creamy Vegan Cucumber Salad with Dill and Red Onion
I hope you enjoy this vegan and gluten-free grilling recipe! We love eating outside whenever possible, and lately, grilled mushrooms are my number one craving and favorite thing to make! If you make this recipe, I hope you'll tag me on Instagram so I can see your delicious finished dish. I also have an Easy Summer Vegan Meal Plan filled with recipes for a full week of delicious plant-based eating, and you can get an overview of the recipes and meal plans on my site in my Vegan Eating Resource Guide.
More Grilling Recipes
- Grilled Veggie Pesto Pasta
- Rainbow Veggie Kebabs with Chimichurri Sauce
- Grillable Quinoa Black Bean Veggie Burger
- Grilled Sweet Potato Fries
- Quinoa & Mango Stuffed Grilled Avocado
- Vegan and Gluten-Free Grilled Peach Cobbler
If you're getting excited about grilling outdoor dinners, you have to try Grilled Portobello Mushrooms and Onions made with a simple marinade. I love to enjoy them on burger buns and make a Portobello Mushroom Burger with the grilled onions. I also love to slice everything up and enjoy in tacos or on a bed of brown rice or quinoa along with my favorite sauce.
- 4 portobello mushrooms, stems trimmed
- 1 medium red onion, sliced in ½-inch rings
- 2 tablespoons extra virgin olive oil
- 1 tablespoon maple syrup
- 2 large garlic cloves, pressed through a garlic press or finely minced
- 1 teaspoon Dijon mustard
- 1 teaspoon fine salt
- ¼ teaspoon ground black pepper
- Preheat grill with the burners on medium heat. Scrub the grill grates clean if needed.
- Clean, dry and place the mushrooms and onion rings on a large flat platter or half sheet baking sheet. Set aside.
- Prepare the marinade. Whisk together the oil, maple syrup, garlic, mustard, salt and pepper. Use a silicone brush to coat all sides of the mushrooms and onions well. If you have time allow the marinade to soak into the mushrooms and onions for about 15 minutes.
- Place the marinated portobello mushrooms and onion rings directly on the grill directly over medium heat (not offset from the burner). Cook for 8 minutes per side with the grill covered until each side has charred grill marks. Mushrooms should be knife-tender. Onions should be soft and slightly charred as well.
- Remove from grill and serve while hot. You can serve the mushrooms and grilled onion rings on a platter with my green tahini sauce, pesto, whipped feta dip, jalapeno chimichurri sauce or chermoula sauce. Serve with brown rice and hummus for a complete meal. Alternatively, serve the portobello mushroom as a "burger" on toasted whole grain bun with the grilled onion rings, lettuce, tomato and my vegan honey mustard sauce.