These grilled portobello mushrooms are topped with butter, garlic, rosemary, and soy sauce for an incredible and indescribable umami richness.
These grilled portobello mushrooms are grilled under perfectly tender and dripping with a savory blend of butter, rosemary, garlic, and a sorta unexpected secret ingredient. While the grill is preheating, simply combine the butter ingredients, and your work is done. The ‘shrooms play nicely alongside anything else you toss on the grill or stand in as a laudable vegetarian or vegan burger. We suspect they’ll be what everyone’s talking about at the table.–Angie Zoobkoff
Grilled Portobello Mushrooms
- 1 stick (4 oz) unsalted butter softened
- 2 garlic cloves finely chopped
- 1 to 2 rosemary sprigs leaves chopped, stalks reserved (1 to 2 tablespoons)
- 2 teaspoons dark soy sauce or tamari
- 8 to 12 large portobello* or firm, meaty, flat-cap mushrooms stalks intact
- Olive oil
- Sea salt and freshly ground black pepper
- Set up your grill for direct and indirect cooking over medium heat and preheat it to 400°F (200°C).
- In a small bowl, stir together the butter, garlic, chopped rosemary leaves, and soy sauce, then season with pepper. Set aside at room temperature.
- Wipe the mushrooms with damp paper towels to clean, if necessary, and trim the ends of the stalks. Place the mushrooms on a rimmed baking sheet, drizzle with a little oil, season with salt and pepper, and toss to coat.
- Turn the mushroom caps gill-side up on the baking sheet. Using a spoon, draw a line in the butter divvying it in half. Spoon half the butter on the mushrooms, dividing it evenly among them.
- If desired, dampen the rosemary stalks with a little water and throw them directly on the charcoal or place them across the grate of your gas grill over direct heat. Place the mushrooms, gill-side up, on the grill over direct heat and close the lid. Grill the mushrooms until softened and the tip of a sharp knife can easily be inserted into the thickest part, 5 to 7 minutes.
- Move the cooked mushrooms to the perimeter of the indirect heat zone. Divide the remaining butter evenly among them and wait for a minute or two to let the butter melt before serving.
*What other mushrooms can I cook on my grill?The best mushrooms for cooking on the barbecue are the meaty ones: porcini, king oyster, or big flat portobellos. You need firm, sturdy fungi to stand up to the heat of the charcoal and develop a crust while staying juicy inside.
Recipe Testers' Reviews
This method for grilled portobello mushrooms is simply fantastic and I'll be making it again and again with all the different compound butters in my repertoire.
The method is perfect—as the mushrooms grill, their juices release into the center of the mushroom and mingle with the butter, resulting in super flavorful, tender mushrooms. I'm not sure if the rosemary sprigs added anything or not—the rosemary flavor was already very pronounced from the butter.
I made these grilled portobello mushrooms for dinner on a Sunday evening after a day filled with yard work. It was a lovely spring day and making something on the grill made it feel like summer was nearly here. The mushrooms were perfect for a busy day because they required very little effort from start to finish and yet they were full of garlicky flavor and satisfying. They would be a great vegetarian option to add to the barbecue for any summer gathering.
The garlic and soy were the most prominent flavors and while we enjoyed them, in the future I would increase the amount of rosemary (I used about 1 tablespoon) so it would also come through.
The grill temperature when we started cooking was 350°F (177°C). It went down to 300°F (149°C) while I divided the butter between the first batch of mushrooms on the grill. By the time the 2nd batch went on the grill, the temperature was back up to 350° and this time the exterior of the mushrooms looked soft and darker brown and the gills were shiny dark brown.
I served the mushrooms as a main with asparagus and roasted potatoes on the side. We also enjoyed these mushrooms sliced as a topping for pizza with feta and bacon.
Originally published September 12, 2019