If you’re looking for a delicious vegetarian entree, try this recipe for stuffed portobello mushrooms! Topped with veggies, marinara sauce, melty mozzarella, and toasted seasoned breadcrumbs, these healthy stuffed mushrooms are a crowd pleaser. Plus, you can assemble them ahead of time!
Packed with spinach, onions, and even the stems from the portobello mushrooms (no waste!), you can count on lots of nutritious vegetables with this recipe.
I love how the mozzarella cheese melts into every bite. The breadcrumbs get golden brown and perfectly toasted on top. These stuffed mushrooms taste a bit like pizza, so it’s a great way to satisfy that craving in a healthier way.
And if you want a little more substance and protein, you can also add Italian sausage or pepperoni.
How to prepare the portobello mushroom caps
First, you’ll need to roast the portobello mushroom caps before adding the filling. Otherwise, they won’t cook enough and will be less flavorful and soft. Here’s what to do.
- Clean the mushrooms by rinsing under water and shaking as much water off as possible, or simply wiping them clean with a damp towel.
- Remove the stems using a small paring knife and slicing as close to the base as possible. Set the stems aside- you’ll use them in a bit!
- Brush the mushrooms on the top and bottom with olive oil, and season with salt and pepper.
- Roast the mushrooms in a 425 degree oven for about 20 minutes, stem-side up.
- Remove any pooled liquid from the inside of the mushroom caps. You can turn them over to drain it out, but I think it’s easiest to use a paper towel, held by tongs so you don’t burn yourself, to absorb as much of it as possible.
How to make the filling
- Sauté some diced onions and the chopped portobello mushroom stems in a little olive oil.
- Once they’re softened, add some fresh baby spinach to the skillet. Let it wilt (this will only take a minute or so!).
- Add some chopped garlic and sauté until fragrant, for only about 30 seconds to a minute (overcooked garlic can be bitter tasting).
- Finally, stir in some marinara sauce (or even homemade pizza sauce) and you’re good to go!
I like to make the filling while the mushrooms are roasting, to save time.
How to make stuffed portobello mushrooms
- Mix some breadcrumbs with a little olive oil and some dried oregano. The olive oil is essential here for getting perfectly golden, toasted breadcrumbs that aren’t burned or too dry. You can also use Italian Style Seasoned Breadcrumbs and omit the dried oregano.
- Divide the filling evenly on each portobello mushroom cap.
- Top with cheese, and sprinkle on the breadcrumbs.
Tips and tricks
- If the stems on the portobello mushrooms are particularly long, you may need to discard the end of it, as it can be too tough. You can save these to make vegetable stock, if you want.
- I recommend using a rimmed baking sheet, lined with foil, with a wire baking rack nestled inside of it to make stuffed mushrooms. There will be liquid that is released while it bakes, and the rack helps elevate the mushrooms so they don’t get soggy. The foil makes for very easy clean up.
Do I need to remove the gills from the mushroom?
Nope! The gills are perfectly edible.
The only reason why you’d want to remove the gills is if you are cooking something that needs to be light colored. The gills impart a very dark color into whatever you’re cooking, which can be off-putting in certain dishes (like if you’re making a mushroom bolognese, for example, and want the red sauce to stay red).
For stuffed mushrooms, this doesn’t matter, as your eyes will be drawn to the golden brown breadcrumbs and bright red marinara sauce.
Can I make these ahead of time?
Yup! Just assemble them as directed, topping them with mozzarella and breadcrumbs. Then, cover and store in your fridge for up to three days until you’re ready to bake them.
Can I add meat to these?
Absolutely! This is a great way to make them higher in protein.
I recommend using ground Italian sausage (hot, mild, or sweet will work). Brown it in the skillet with the onions and mushroom stems, then proceed as directed.
You could also layer some pepperoni on there too, in between the cheese and breadcrumbs layer. Or, you can make these low carb by omitting the breadcrumbs and using pepperoni instead.
Other easy mushroom recipes:
- Perfectly browned sautéed mushrooms
- One pot orzo with mushrooms and brown butter
- Italian Vegetarian Stuffed Mushrooms
- Salisbury Steak with Mushroom Gravy
- Beef Barley Soup with Mushrooms
Be sure to check out all my vegetarian recipes!
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Stuffed Portobello Mushrooms
- Preheat your oven to 425 degrees F. Arrange a wire baking rack inside a rimmed baking sheet (lined with foil, if desired).
- Wash the portobello mushrooms off and dry with clean paper towels. Use a paring knife to slice the stems off, and use your hands to pull off any soft parts of the mushroom along the edge that overlaps the gills. Reserve these parts.
- Place the mushrooms stem side down on the rack in the baking sheet. Brush with 1/2 tablespoon of olive oil and season with salt and pepper. Turn them stem side up and repeat on the other side with the remaining 1/2 tablespoon olive oil. Roast in preheated oven for 20 minutes.
- While the mushrooms are roasting, chop up the stems and any other scraps from the mushrooms. Sauté the onion and chopped mushroom in 1 tablespoon of the olive oil in a medium skillet over medium-high heat with a pinch of salt and pepper until softened and starting to brown (about 3 minutes). Add the baby spinach and sauté until wilted (about 1 minute). Add the chopped garlic and sauté until fragrant (about 1 minute). Add the marinara sauce (1 cup) and stir together. Turn off heat.
- In a small bowl, mix together the breadcrumbs (1/4 cup), remaining 1 tablespoon of olive oil, dried oregano (1 teaspoon), and a pinch of salt and pepper.
- Remove mushrooms from oven. You may notice pools of liquid inside each cap. Use a paper towel held by tongs to press down in each cap to absorb as much liquid as you can.
- Divide the marinara mixture evenly into each mushroom cap, followed by 1/4 cup of mozzarella cheese on each. Sprinkle each evenly with the breadcrumb mixture.
- Continue baking at 425 degrees F for 10-15 more minutes, until cheese is melted and breadcrumbs are toasted. Serve hot.
- For a lower carb version, omit the breadcrumbs and top with fresh grated parmesan cheese and sprinkle with oregano before baking. Or, top with pepperoni or a low carb alternative, like crumbled pork rinds.
- For a gluten-free version, use gluten-free breadcrumbs.
- For a vegan version, use your favorite vegan cheese substitute for the mozzarella.
- Make it ahead: bake the mushrooms and assemble them as directed and store in the refrigerator for up to three days. Bake for a few more minutes straight from the fridge so they warm through the whole way.