Juicy portobello mushroom burgers are topped with flavor-loaded romesco sauce to create the ultimate plant-powered burger. Even the biggest of carnivores in your life will go wild for these delicious hand-held delights. 
This may be the meatiest meatless burger your mouth will ever meet.
I’m actually in awe that is this is first portobello burger recipe I’ve posted because I have a serious love obsession with them. Said obsession is actually pretty broad because I deeply love most burgers in general. Beef, black bean, bison, turkey – I don’t discriminate. As long as the bun is toasty, the toppings are plentiful and I’ve got 10 wet-naps by my side, I’m rockin’ and rollin’.
I like to marinate the mushroom caps for at least an hour before grilling (or pan searing) them. A simple marinade of balsamic, olive oil, garlic and herbs does the job deliciously and makes the ‘shrooms extra juicy and flavorful. You can throw these bad boys on an outdoor grill or cook them stove top in a grill pan or standard saute pan.
Paired with a tomato and mozz salad, crusty bread and perhaps a light crispy brew, you’re looking at the perfect late summer feast!
But what really brings these burgers from a 10 to a “I can’t even” is that tangy, vibrant, luscious romesco sauce.
Besides its gorgeous fire-orange hue, the best thing about this versatile sauce is that it comes together in only 5 MINUTES. Just chuck everything in the blender or food processor and let the work be done for you. Your only job is to taste test and then literally slather it on everything.
Poached eggs. Salads. Pasta. Pizza. Zoodles (YASS). Get wild with it. The only place it doesn’t belong is on your shirt (oops). 
Speaking of shirts (great segue, I know), It’s currently Thursday evening and our flight to Chicago leaves in, oh….8 hours , and I’m not even fully packed yet (haha…ha).
You know when you just have an inherent desire to be exceptionally lazy? Yep, current status. I’ll probably end up overpacking, forgetting something important (like my hairbrush, which actually wouldn’t be the worst thing) and then strolling into the airport like a zombie with two different shoes on.
Wouldn’t be the first time and surely won’t be the last. 
But back to business. The business of TOPPINGS.
They don’t need much between the flavor bomb romesco sauce and marinated ‘shrooms, but I’m never one to vote against a few extra toppings. I sliced and grilled a big ol’ red onion and combined it with fresh baby spinach and sliced avocado. A little crisp, a little crunch, a whole lotta freshness. 
Give these hearty, plant-powered burgers a try for dinner this week and I can promise you will NOT be disappointed. The leftover romesco sauce is yours to get creative with. Just be sure you snap a pic and tag me so I can see your drool-worthy creations.
- 4 portobello mushroom caps, cleaned and stems removed
- ⅓ cup balsamic vinegar
- 3 tbsp extra virgin olive oil
- 1 tsp dried herb mix (Italian, Herbes de Provence, etc)
- 2 cloves garlic, minced
- Sea salt and black pepper to taste
- 4 buns of choice
- Optional toppings: 1 red onion, 1 avocado, 2 cups fresh baby spinach
- **Romesco Sauce**
- 1 (12 ounce) jar roasted red peppers, drained
- 4 whole peeled plum tomatoes (I use canned)
- ¼ cup slivered almonds, toasted
- 1 tbsp extra virgin olive oil
- 2 cloves garlic
- 2 tbsp parmesan cheese
- 3 tbsp fresh parsley
- ½ tsp smoked paprika
- Sea salt and black pepper to taste
- Begin marinating mushrooms by combing balsamic, olive oil, herbs, garlic and a pinch of salt and pepper in a large bowl. Add mushroom caps and use a spoon to dredge with marinade. Marinate at room temperature for a minimum of 1 hour, spooning mix over mushrooms every so often.
- Heat a grill pan (or saute pan) over medium heat. Cook mushrooms for 4-5 minutes per side, spooning remaining marinade overtop. Remove from pan and set aside. At this point, you can choose to grill onions and/or buns on heated pan.
- Combine romesco sauce ingredients in a blender or food processor. Blend until ingredients emulsify and form a sauce. I like my sauce to be a little chunky but you can choose to blend it longer until smooth.
- To assemble - add one portobello mushroom cap to each bun. Add toppings of choice and coat with romesco sauce. Serve!
If you like this recipe, be sure to check out some of my favorite vegetarian hand-helds:
Cauliflower Hummus Burgers with Green Goddess Sauce
Smoky Chickpea Burgers with Cilantro-Lime Apple Slaw
I'm Jamie - A Registered Dietitian, recipe developer, and full-fledged foodie inspiring you to live deliciously. 
Ahhhmazing! The flavor combination was exquisite. By far the best portobello burger I ever ate. Needless to say, I’m hooked!
Hi Lori! I’m so glad to hear!! This is one my favorite summertime recipes. Thanks for leaving a review!
I’ve always loved pasta with romesco. I’ll have to try this!