Grilled Arugula and Portobello Mushroom Sandwich

This grilled sandwich features flavorful portobello mushrooms and peppery arugula, all sandwiched between two slices of crusty bread.

Ingredients - Serves 2

Preheat the grill or grill pan over medium heat.
Clean the portobello mushrooms and remove the stems.
In a small bowl, whisk together the olive oil, balsamic vinegar, minced garlic, salt, and pepper.
Brush the mushroom caps with the marinade mixture.
Grill the mushrooms for about 5-7 minutes per side, or until tender.
While the mushrooms are grilling, spread mayonnaise and Dijon mustard on one side of each slice of bread.
Layer the arugula, grilled mushrooms, tomato slices, and red onion on two slices of bread.
Top with the remaining slices of bread, mayo and mustard side down.
Place the sandwiches on the grill or grill pan and cook for 2-3 minutes per side, or until the bread is toasted and the cheese is melted.
Remove from the grill, slice in half, and serve hot.