Have you ever made a portobello pizza? They're really quite incredible! A portobello mushroom cap is a perfect vehicle to created gluten-free, low carb pizzas or melted sandwiches. These mushrooms are basically big crimini mushrooms that have grown to 4 to 6 inches in diameter. When you remove the woody stem, what remains is the delicious, meaty mushroom. The recipe below takes full advantage of the portobello's ability to become sandwich "bread."
You can make so many different kinds of sandwiches on a portobello mushroom, but this recipe for a low carb tuna sandwich is my favorite. Once you've melted the cheese on top of that savory tuna salad, you'll swear this recipe couldn't possibly be healthy!
Low Carb Tuna Sandwich 
Ingredients2 (6-ounce) cans Albacore Tuna packed in water, drained
1/2 cup Greek yogurt
1 small red onion, small diced
1 tablespoon sweet pickle relish
1 teaspoon dried oregano
1/2 teaspoon garlic powder
1 tablespoon capers, drained and rinsed
Salt and pepper to taste
4 large Portobello mushrooms
1 small roma tomato, sliced
1 cup mozzarella cheese
Directions1. Preheat the oven to 375 degrees F. Line a baking sheet with an oven-safe rack and set aside.
2. In a large bowl, combine the drained tuna, Greek yogurt, onion, pickle relish, oregano, garlic powder, and capers. Season with salt and pepper to taste.
3. Clean the tops of the mushrooms with a damp paper towel. Remove the mushroom stems and scoop out the black gills using a spoon. Discard everything except the mushroom cap.
4. Place the mushroom caps gill-side up on the baking sheet. Fill the mushrooms with the tuna mixture and top them with the sliced tomatoes.
5. Top the mushrooms with the mozzarella cheese.
6. Bake for 20 minutes, until the cheese is melted and slightly browned.
