This vegetarian, gluten-free Italian Grilled Portobello Caprese Sandwich pairs fresh mozzarella, ripe tomatoes and basil between two large portobello mushrooms for a delicious, melty bite.
Welcome to Sandwich Week — a celebration of handheld meals with recipes ranging from hearty chicken sandwiches to vegetarian favorites. This Portobello Caprese Sandwich is a standout for anyone seeking a gluten-free, meatless option that still feels substantial and satisfying. Using two large portobello caps in place of bread creates a unique, low-carb presentation while letting classic Caprese flavors shine: sun-dried tomato pesto, fresh mozzarella, tomato and basil.
What makes this sandwich special is its balance of textures and flavors. The portobello mushroom provides a meaty, savory exterior; sun-dried tomato pesto and crushed garlic add richness and depth; while fresh mozzarella and basil offer creaminess and bright herbal notes. Additional fillings like sliced peperoncini and roasted bell peppers introduce a pleasant tang and sweetness, making every bite layered and interesting.
Portobello Caprese Sandwich Ingredients
- 2 large portobello mushrooms
- 2 tbsp sun-dried tomato pesto
- 1 tsp garlic, crushed
- 1/2 cup fresh mozzarella, sliced
- 1/2 roma tomato, sliced
- 4–6 large fresh basil leaves
- 1/4 cup sliced peperoncinis
- 1/2 cup roasted bell peppers
- Olive oil cooking spray
Portobello Caprese Sandwich Instructions
- Heat a grill to medium or preheat your oven to 400°F (200°C).
- Clean the portobello caps by removing the stems and scraping out the gills with a spoon. Be gentle to keep the caps intact so they hold the filling.
- Spread 1 tablespoon of sun-dried tomato pesto inside each mushroom cap. Sprinkle 1/2 teaspoon crushed garlic over the pesto on each cap.
- Place a large slice of fresh mozzarella onto each portobello cap.
- On one cap, layer the sliced roma tomato and fresh basil leaves over the mozzarella.
- On the other cap, add the sliced peperoncinis and roasted bell peppers.
- Carefully bring the two filled caps together so they form a sandwich.
- Lightly spray the grill grates with olive oil cooking spray to prevent sticking. Place the assembled sandwich on the grill and cook for about 20 minutes, flipping carefully halfway through so both sides heat evenly and the mozzarella melts.
- If you don’t have a grill, place the assembled sandwich on a rimmed baking sheet and bake in the preheated oven for 20 minutes or until the cheese is melted and the mushrooms are tender.
- Remove from the grill or oven, let rest for a minute, then slice in half and serve warm.
Serving Suggestions & Tips
- Serve with a simple mixed green salad or a side of roasted vegetables for a light meal.
- To make this sandwich vegan, swap the fresh mozzarella for a plant-based cheese that melts well, or use a creamy cashew-based spread.
- For extra flavor, drizzle a little balsamic glaze over the tomato and basil before closing the sandwich.
- If mushrooms are small, use two caps per sandwich or serve open-faced (one cap topped) as a main course.
- To avoid a soggy sandwich, pat tomato slices dry before assembling, and don’t over-saturate the portobello with sauce.
Storage and Make-Ahead
Assembled sandwiches are best cooked and eaten right away for maximum texture and flavor. If you need to prepare elements ahead of time, slice the tomatoes, roast the peppers, and store the pesto separately in airtight containers in the refrigerator for up to 2–3 days. Leftover grilled portobello sandwiches can be refrigerated for up to 2 days and reheated gently in a 350°F oven until warmed through.
Nutritional Highlights (per sandwich)
- Calories: 284 kcal
- Carbohydrates: 18 g
- Protein: 18 g
- Fat: 16 g (Saturated Fat: 8 g)
- Sodium: 1606 mg
- Fiber: 5 g
- Vitamin C: 64.4 mg
- Calcium: 340 mg
This Portobello Caprese Sandwich is a simple, flavorful vegetarian option that’s easy to adapt and perfect for summer grilling or cozy indoor roasting. Enjoy the melty mozzarella, bold pesto and vibrant produce in every bite.