Quick Recipe Version (TL;DR)
Quick Ingredients
- 4 large portobello caps, stems removed and gills scraped
- 3 tbsp olive oil, plus 1 tbsp for spinach and 2 tbsp for breadcrumbs
- 1 tsp kosher salt, 1/2 tsp black pepper
- 10 oz baby spinach; 3 garlic cloves, minced; pinch red pepper flakes
- 3/4 cup panko; 2 tbsp chopped parsley; 1 tsp lemon zest; 1/2 tsp dried oregano; 2 tbsp grated Parmesan (optional)
- 1 cup shredded mozzarella (4 oz) or 3/4 cup crumbled feta (4 oz)
- 5 oz arugula; 1/4 small red onion, thinly sliced
- 1 lemon (2 tbsp juice + extra wedges); 2 tbsp extra-virgin olive oil
Do This
- 1. Heat oven to 425°F (220°C). Line a rimmed sheet pan.
- 2. Brush caps with 3 tbsp oil; season with 1/2 tsp salt and 1/4 tsp pepper. Roast gill-side up 10 minutes; drain liquid.
- 3. Sauté garlic in 1 tbsp oil; add spinach and a pinch of flakes. Cook 2–3 minutes; squeeze dry and chop. Season with 1/4 tsp salt.
- 4. Mix panko, parsley, lemon zest, oregano, Parmesan (if using), 2 tbsp oil, and a pinch of salt.
- 5. Fill caps with spinach, then mozzarella or feta; top with herbed breadcrumbs.
- 6. Roast 9–12 minutes until cheese melts and crumbs are golden; broil 1–2 minutes if needed.
- 7. Toss arugula and onion with lemon juice, 2 tbsp oil, 1/4 tsp salt, and pepper. Serve alongside with lemon wedges.
Why You’ll Love This Recipe
- Big, meaty portobellos stay juicy while the garlicky spinach keeps the filling vibrant and flavorful.
- Choose your cheese adventure: melty mozzarella for comfort or tangy feta for a Mediterranean twist.
- Golden, herbed breadcrumbs add irresistible crunch without deep frying.
- A bright, lemony side salad balances every bite and turns this into a complete, fresh-feeling meal.
Grocery List
- Produce: 4 large portobello caps, 10 oz baby spinach, 3 garlic cloves, 1 lemon, 5 oz arugula, 1/4 small red onion, fresh parsley
- Dairy: Shredded mozzarella or feta, Parmesan (optional)
- Pantry: Olive oil, extra-virgin olive oil, panko breadcrumbs, dried oregano, kosher salt, black pepper, red pepper flakes
Full Ingredients
For the Mushrooms
- 4 large portobello mushroom caps (about 5 inches wide), stems removed and gills scraped
- 3 tbsp olive oil
- 1/2 tsp kosher salt
- 1/4 tsp freshly ground black pepper
Garlicky Spinach
- 1 tbsp olive oil
- 3 garlic cloves, finely minced
- 10 oz baby spinach
- Pinch red pepper flakes (optional)
- 1/4 tsp kosher salt, plus more to taste
Herbed Breadcrumbs
- 3/4 cup panko breadcrumbs
- 2 tbsp extra-virgin olive oil
- 2 tbsp finely chopped fresh parsley
- 1 tsp finely grated lemon zest
- 1/2 tsp dried oregano
- 2 tbsp finely grated Parmesan cheese (optional)
- Pinch kosher salt
Cheese (Choose One)
- 1 cup shredded low-moisture mozzarella (4 oz), or
- 3/4 cup crumbled feta (4 oz)
Lemony Side Salad
- 5 oz arugula (about 5 cups lightly packed)
- 1/4 small red onion, very thinly sliced
- 2 tbsp freshly squeezed lemon juice
- 2 tbsp extra-virgin olive oil
- 1/4 tsp kosher salt
- Freshly ground black pepper, to taste
To Serve
- Lemon wedges
- Extra chopped parsley, for garnish
- Red pepper flakes, to taste (optional)
Step-by-Step Instructions
Step 1: Heat the oven and prep the mushrooms
Preheat the oven to 425°F (220°C). Line a rimmed sheet pan with parchment for easy cleanup. Wipe the portobello caps with a damp paper towel. Remove stems and use a spoon to gently scrape out the dark gills so the caps can hold more filling and won’t turn the stuffing muddy.
Step 2: Pre-roast the caps to drive off moisture
Brush both sides of the caps with 3 tbsp olive oil and season with 1/2 tsp kosher salt and 1/4 tsp black pepper. Place gill-side up on the pan and roast for 10 minutes. Tip out any pooled liquid from the caps and blot the pan if needed. This step keeps the final dish juicy, not soggy.
Step 3: Sauté the garlicky spinach
While the caps pre-roast, warm 1 tbsp olive oil in a large skillet over medium heat. Add the minced garlic and cook 30 seconds until fragrant. Add the spinach and a pinch of red pepper flakes. Toss until wilted, 2–3 minutes. Transfer to a colander; when cool enough to handle, squeeze out as much moisture as possible, then chop. Season with 1/4 tsp salt (taste and adjust).
Step 4: Mix the herbed breadcrumbs
In a bowl, combine panko, 2 tbsp extra-virgin olive oil, parsley, lemon zest, oregano, Parmesan (if using), and a pinch of salt. Toss to coat so the crumbs are evenly moistened; this helps them toast golden and stay crisp.
Step 5: Assemble the stuffing
Divide the chopped spinach among the pre-roasted caps, pressing gently to level. Top with your cheese choice: mozzarella for gooey melt or feta for tangy pockets. Sprinkle the herbed breadcrumbs evenly over the cheese. If the crumbs look dry, drizzle with another teaspoon of olive oil.
Step 6: Roast until melty and golden
Return the stuffed caps to the oven and roast 9–12 minutes, until the cheese is melted (or feta is heated through) and the crumbs are deeply golden. For extra color, switch to broil for 1–2 minutes, watching closely. Let rest 2–3 minutes so juices settle.
Step 7: Toss the lemony side salad
In a large bowl, whisk 2 tbsp lemon juice with 2 tbsp extra-virgin olive oil, 1/4 tsp salt, and several grinds of black pepper. Add arugula and thinly sliced red onion; toss to lightly coat. Taste and adjust seasoning.
Step 8: Plate and garnish
Serve one stuffed portobello per person alongside a mound of the lemony salad. Garnish mushrooms with extra parsley and a pinch of red pepper flakes if you like heat. Add lemon wedges for squeezing over the hot mushrooms just before eating.
Pro Tips
- Pre-roasting is key. It concentrates flavor and prevents sogginess.
- Squeeze the spinach well. Excess moisture will soften the crumb topping.
- Oil the panko. Lightly oiled crumbs brown evenly and stay crisp.
- Choose cheese wisely. Use mozzarella for melty pull; feta for briny tang. If using feta, go lighter on added salt.
- Don’t skip the rest. A brief 2–3 minute rest keeps juices in the mushrooms, not on the plate.
Variations
- Mediterranean Feta: Add 2 tbsp chopped Kalamata olives and 2 tbsp chopped sun-dried tomatoes with the spinach; finish with a drizzle of extra-virgin olive oil.
- Caprese Mozzarella: Add 1/2 cup halved cherry tomatoes under the mozzarella and finish with torn basil and a balsamic glaze drizzle.
- Vegan & Gluten-Free: Use plant-based mozzarella and nutritional yeast in place of Parmesan; swap in gluten-free panko.
Storage & Make-Ahead
Pre-roast the mushroom caps and cook/squeeze the spinach up to 2 days ahead; refrigerate separately in airtight containers. Assemble just before roasting. Leftover cooked mushrooms keep 3 days refrigerated; reheat on a sheet pan at 375°F (190°C) for 10–12 minutes until hot and crisp. Freezing is not recommended as mushrooms can turn watery.
Nutrition (per serving)
Approximate with mozzarella: 420 calories; 26 g fat; 30 g carbs; 5 g fiber; 19 g protein; 840 mg sodium. Using feta changes macros slightly (more sodium, a bit less protein).
