A stuffed portobello mushroom cut in half with cheese and breadcrumbs on top.
Print Recipe
5 from 1 vote

Stuffed Portobello Mushrooms

These vegetarian stuffed portobello mushrooms are a healthy recipe packed with baby spinach, marinara, and topped with mozzarella cheese.
Prep Time15 mins
Cook Time30 mins
Total Time45 mins
Course: Main
Cuisine: Italian
Servings: 4 servings
Calories: 255kcal
Author: Elizabeth Lindemann



  • 4 large portobello mushroom caps 4-6" in diameter
  • 3 tablespoons extra-virgin olive oil divided
  • kosher salt and black pepper
  • 1 small yellow onion diced (or 1/2 large)
  • 2 cups baby spinach
  • 2 cloves garlic chopped
  • 1 cup marinara sauce
  • 1/4 cup breadcrumbs
  • 1 teaspoon dried oregano
  • 1 cup shredded mozzarella cheese


  • 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.


Serving: 1stuffed mushroom | Calories: 255kcal | Carbohydrates: 16g | Protein: 11g | Fat: 18g | Saturated Fat: 5g | Cholesterol: 22mg | Sodium: 567mg | Potassium: 667mg | Fiber: 3g | Sugar: 7g | Vitamin A: 1861IU | Vitamin C: 11mg | Calcium: 196mg | Iron: 2mg