Cheese-Stuffed Portobello Mushrooms with Spinach and Walnuts

By , Test Kitchen Director · Reviewed by AislePrompt Editorial · ·

Large Portobello mushrooms filled with a creamy blend of cheeses, sautéed spinach, and crunchy walnuts for a rich keto vegetarian dish. This mediterranean-inspired keto (vegetarian) ready in about 35 minutes pairs large Portobello mushrooms, cream cheese, mozzarella cheese for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 330 calories and feeds 4, so it slots cleanly into a low-carb week and pairs well with cauliflower rice or roasted green vegetables. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

★ 4.2 (11 ratings) Prep: 15 min Cook: 20 min Serves 4 Mediterranean cuisine 330 cal/serving
Build a week of meals around this recipe → Shop this recipe on Instacart → Shop equipment ↓

Ingredients

Equipment for this recipe

Top-rated tools to make this recipe successfully.

More Bakeware & baking tools → Shop all kitchen tools →

Instructions

  1. Step 1: Preheat oven to 375°F. Brush 4 large Portobello mushrooms with 2 tbsp olive oil and sprinkle with 1/2 tsp salt and 1/4 tsp black pepper. Place on a baking sheet gill side up.
  2. Step 2: Heat 1 tbsp olive oil in a skillet over medium heat. Add 2 minced garlic cloves and sauté for 30 seconds until fragrant. Add 2 cups chopped fresh spinach and cook for 3-4 minutes until wilted. Remove from heat.
  3. Step 3: In a bowl, mix 4 oz softened cream cheese, 1/2 cup shredded mozzarella cheese, sautéed spinach, 1/4 cup chopped walnuts, 1/2 tsp salt, 1/4 tsp black pepper, and optional 1/4 tsp red pepper flakes until well combined.
  4. Step 4: Spoon the cheese and spinach mixture evenly into each mushroom cap. Bake in the preheated oven for 15-18 minutes until the mushrooms are tender and the cheese filling is bubbly and lightly browned on top. Serve warm as a rich, satisfying keto vegetarian entree.

Frequently asked questions

How long does Cheese-Stuffed Portobello Mushrooms with Spinach and Walnuts take to make?

Total time is about 35 minutes (15 min prep + 20 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Cheese-Stuffed Portobello Mushrooms with Spinach and Walnuts?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep large portobello mushrooms from drying out.

Can I substitute ingredients in Cheese-Stuffed Portobello Mushrooms with Spinach and Walnuts?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Cheese-Stuffed Portobello Mushrooms with Spinach and Walnuts for a different number of people?

The recipe is written for 4 servings. Multiply each ingredient by (your serving target / 4). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

Is Cheese-Stuffed Portobello Mushrooms with Spinach and Walnuts keto?

Yes — this recipe is tagged keto, vegetarian, gluten free, low carb based on its ingredient list. Always cross-check labels for packaged ingredients (sauces, broths, condiments) since formulations vary by brand.

What others are saying

Related recipes