Spinach stuffed portobello mushrooms are delicious and so pretty. They work well as an appetizer, or you can serve them as a tasty side dish.
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. Stuffed portobello mushrooms are delicious and so very pretty. And surprisingly, they're not that difficult to make! So I like to make them for guests, but I also make them quite often for my family.
The ingredients you'll need
You'll only need a few simple ingredients to make this tasty portobello recipe (the exact measurements are listed in the recipe card below):
Portobello mushrooms: Try to find mushrooms that aren't too shallow or too deep. You wan them to perfectly showcase the filling.
Olive oil cooking spray: I find 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 might want to use less salt.
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.
Grated Parmesan: Make sure you use finely grated parmesan and not coarsely shredded.
How to make stuffed portobello mushrooms
Scroll down to the recipe card for the details. It's not a difficult recipe to make! Here are the basic steps:
Pre-broil. You start by briefly broiling the mushrooms.
Saute. Then, you saute spinach, onions, and garlic in olive oil.
Stuff. Mix in Parmesan, and stuff the mixture inside the portobello mushrooms.
Broil. Finish by broiling briefly, just until the filling is golden.
How to prevent the mushrooms from becoming soggy
Cooked mushrooms can become soggy. To avoid sogginess:
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 baking or broiling, broil or bake briefly, just until topping is browned.
Baking 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.
How to serve stuffed portobello mushrooms
They 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.
What about 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 on 50% power.
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Stuffed Portobello Mushrooms
- 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, divided
- 1 small onion, finely chopped (6oz)
- 1 tablespoon minced fresh garlic
- ¼ cup grated Parmesan
- Preheat broiler, setting the temperature to high. Set an oven rack in the middle of the oven (you don't want the mushrooms too close to the heating element for this recipe). Line a broiler-safe rimmed baking sheet with foil.
- Wipe the mushrooms clean with a damp paper towel. Gently twist off or the stem of each mushroom. Holding each mushroom in one hand, use a spoon to gently scrape out the gills.
- Spray the mushroom caps with olive oil cooking spray on both sides. Sprinkle with ½ teaspoon kosher salt and ⅛ teaspoon black pepper. Broil 5 minutes on each side, or until just tender.
- Meanwhile, defrost the spinach in the microwave according to the directions on the package (my package said to cut a small slit in the wrapper, place on a microwave-safe plate and microwave for 4-6 minutes). Place in a colander to drain. When cool enough to handle, press on the cooked spinach with your hands and extract as much water as possible out of it. Repeat this until you're sure you can no longer extract more water.
- Remove the mushrooms from oven. Heat 1 tablespoon olive oil in a large skillet over medium heat, about 3 minutes. Add the onion and cook 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, 1-2 more minutes. Remove from heat and allow to cool a few 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 back under the broiler for 2-3 minutes, or until filling is golden.