Hello portobello mushroom burgers! I grew up seeing these as a vegetarian option in restaurants and cafes. But here’s the thing, for mushroom lovers (that would be me, you too?), portobellos are perfect for burgers, whether you are vegetarian or not. The cap of this ginormous cremini is the perfect size and shape of a burger. The mushroom is meaty and juicy and umami-y. Paint the caps with a little olive oil, put them on the grill for a few minutes each side, and you have a perfect grilled mushroom to put between two burger buns. In the following rendition, we’ve layered on grilled onions, some sautéed spinach, and sun-dried tomatoes, but it’s just as good plain, with a little salt and pepper.
- 4 portobello mushroom caps
- Olive oil
- One 8-ounce jar of sun-dried tomatoes in oil
- 8 ounces of baby spinach
- 1 red onion, sliced into 1/4-inch rounds
- 4 hamburger buns
1 Prepare your grill for high, direct heat.
2 While the grill is heating, if you wish, sauté the baby spinach in a tablespoon of olive oil and a sprinkle of salt in a large sauté pan on medium high heat, just until the spinach wilts, then remove to a plate. The gently wilted spinach will stay on the portobello mushroom burger better than raw spinach, which tends to fall off. Or you can use raw baby spinach. Your choice.
2 Wipe the mushrooms clean with a damp paper towel. If you are working with whole mushrooms, slice off the stems (you can use for another purpose, chopped and sautéed or for making stock.) Paint the tops of the mushroom caps with some of the oil from the sun-dried tomatoes.
4 Scrape the grill grates clean. Using a folded up paper towel dipped in olive oil, wipe down the grill grates to oil them. Brush the onion rounds with some olive oil and place them on the grill. Place the mushroom caps on the grill, top side down first. Sprinkle with a little salt. Grill the mushroom caps and the onion rounds for 4-5 minutes per side. Grill the burger buns, cut side down, for about 1/2 to 1 minute, until lightly toasted.
5 To assemble, spread some mayonnaise on each bun. Put a portobello mushroom cap on the bottom, then layer on the spinach, sun-dried tomatoes, and finally some onion. Serve at once.