Stuffed portobello mushrooms are delicious and so pretty. They work well as an appetizer, or you can serve them as a tasty side dish.
The leftovers keep well in the fridge for several days, so sometimes I double the recipe and make a few extra mushrooms.

I love portobellos. They are so tasty, and they are also substantial - almost meaty. I like their bold flavor and dense texture. I enjoy them simply grilled, but filling them with things is especially fun!
This recipe is wonderful. The portobello mushrooms are stuffed with a delicious mixture of spinach, onions, garlic, and parmesan. They're tasty, pretty, and surprisingly easy to make.
Jump to:
Ingredients
You'll only need a few simple ingredients to make this tasty recipe. The exact measurements are listed in the recipe card below. Here's an overview of what you'll need:
- Portobello mushrooms: Try to find mushrooms that aren't too shallow or too deep. You want them to perfectly showcase the filling.
- Olive oil cooking spray: I find that spray is convenient. But you can simply brush them with olive oil.
- Kosher salt and black pepper: I use kosher salt in most of my recipes. If using fine salt, you should use less of it.
- Frozen chopped spinach: I haven't tried making this recipe with fresh spinach. Frozen is convenient, as I always have a bag in the freezer.
- Olive oil: For cooking the filling. You can use butter instead if you'd like.
- Aromatics: Onion and garlic. I'm lazy, so I chop the onion in the food processor and use jarred minced garlic. But if you have the patience, freshly minced garlic cloves will taste better.
- Grated Parmesan: Make sure you use finely grated parmesan and not coarsely shredded.
Instructions
Making stuffed portobello mushrooms is surprisingly easy. Scroll down to the recipe card for the details. Here are the basic steps:
Prep the mushrooms. You'll want to wipe them clean, then remove the stem and gills.
Pre-broil. Spray the mushrooms with olive oil, season them with salt and pepper, then briefly broil them.
Saute. Your next step is to defrost frozen chopped spinach, drain it well, and then saute it with onions and garlic in some olive oil.
Stuff. Mix in Parmesan, then stuff the mixture into the mushrooms.
Broil. Finish by broiling briefly, just until the filling is golden.
Expert tip
I can't stress strongly enough how important it is to thoroughly drain the defrosted spinach. You want no traces of water left! So place it in a colander and press on it repeatedly with the back of a large spoon, until no water comes out.
Frequently asked questions
1. Wipe clean, don't wash the mushrooms - they absorb water.
2. Briefly broil the mushrooms to release some of their water content.
3. In the final stage of broiling, broil briefly, just until the filling is browned. Broiling for too long will result in mushy mushrooms that have released their liquid into your filling.
But even if that happens, you can still salvage the dish. Carefully drain the liquid, and place the mushrooms on paper towels to soak as much of the liquid as you can.
Yes. Scraping out the gills makes room for the filling, improves the mushrooms' texture, and helps reduce excess water.
The mushrooms will still release quite a bit of water as you broil them, so once they're done, place them upside down on paper towels to drain.
As mentioned above, I prefer to wipe them clean with a damp paper towel. Mushrooms are porous, and if you wash them, they'll absorb water and turn out soggy.
If you'd rather wash them, do so briefly, and dry them immediately.
Variations
I love this recipe as is and almost always make it as written. But in case you'd like to vary the basic recipe, here are a few ideas for you:
- You can use butter instead of olive oil. Ghee works too.
- Try adding more seasonings to the spinach mixture. Good options include dried oregano or thyme and a pinch of cumin.
- Sometimes I like to sprinkle the finished dish with red pepper flakes, as shown in the video below.
- Try mixing bacon bits into the spinach mixture. You can add them with the parmesan.
Serving suggestions
Stuffed portobello mushrooms make a great appetizer or side dish if you serve one per person. I often serve them with broiled salmon.
Or you can serve two per person with a couple of fried or poached eggs, for a tasty and filling meatless meal.
Storing leftovers
You can keep the leftovers in the fridge, in an airtight container, for 3-4 days. It's a good idea to place them on paper towels and replace the paper towels daily. Reheat the leftovers in the microwave, covered, on 50% power.
Related recipes
👩🏻🍳 I typically publish a new or an updated recipe once a week. Want these recipes in your inbox? Subscribe! You can unsubscribe at any time.
Recipe card
Stuffed Portobello Mushrooms
INGREDIENTS
- 4 portobello mushroom caps
- olive oil cooking spray
- 1 teaspoon Diamond Crystal kosher salt divided
- ¼ teaspoon black pepper divided
- 10 oz frozen chopped spinach
- 2 tablespoons olive oil
- 1 small onion finely chopped (6oz)
- 1 tablespoon minced fresh garlic
- ¼ cup dry-grated Parmesan
INSTRUCTIONS
- Preheat the broiler, setting the temperature to high (500 degrees F). Set an oven rack in the middle of the oven. Line a broiler-safe rimmed baking sheet with foil.
- Gently wipe the mushrooms clean with a damp paper towel. Twist off or cut off the stem of each mushroom. Use a small spoon to scrape out the gills and discard them.
- Spray the mushroom caps with olive oil on both sides. Sprinkle them with ½ teaspoon kosher salt and ⅛ teaspoon black pepper. Broil until just tender, about 4 minutes per side. Place them upside down on paper towels to drain off any liquids.
- Meanwhile, defrost the spinach in the microwave according to the directions on the package. Place the defrosted spinach in a colander to drain. Repeatedly press on the spinach with the back of a large spoon to remove as much water as possible.
- Heat the olive oil in a large skillet over medium heat. Add the onion and cook it for 5-7 minutes, stirring occasionally, until golden. Add the garlic, spinach, ½ teaspoon kosher salt and ⅛ teaspoon black pepper and cook, stirring to combine everything, for 1-2 more minutes. Remove the skillet from the heat and allow it to cool for a couple of minutes, then mix in the Parmesan.
- Evenly distribute the spinach mixture among the mushrooms. Don't press down on the filling - it's prettier when it's piled high on top of the mushrooms. Place the stuffed mushrooms back under the broiler (on the middle rack) for 2-3 minutes, until the filling is golden. Serve immediately.
WATCH THE VIDEO:
NOTES
- We're setting the oven rack in the middle of the oven because we don't want the mushrooms too close to the heating element for this recipe. They burn easily.
- Scraping out the gills makes room for the filling, improves the mushroom's texture, and helps reduce excess water. The mushrooms will still release quite a bit of water as you broil them, so once they're done, place them upside down on paper towels to drain.
- I can't stress strongly enough how important it is to thoroughly drain the defrosted spinach. You want no traces of water left! So place it in a colander and press on it repeatedly with the back of a large spoon, until no water comes out.
ADD YOUR OWN NOTES
NUTRITION PER SERVING
❤️ Let's connect! Follow me on Pinterest, Facebook, TikTok, YouTube, Instagram, or Twitter.