Makes 1 sandwich

1/2 cup sliced Portobello mushroom (about 1/2 of a small Portobello)
1/4 cup sliced red onion
4-5 grape tomatoes (each sliced in half)
1 teaspoon vegetable oil
1/4 teaspoon balsamic vinegar
pinch of salt
pinch of ground black pepper
pinch of dried thyme
2 slices sourdough bread
butter, softened
1 slice Provolone cheese
1 slice Monterey Jack cheese
1 teaspoon Grey Poupon Country Dijon mustard

Roast the Vegetables: Preheat broiler to high. Combine the mushrooms, onion and tomatoes with with oil and vinegar, and a few pinches of salt and pepper and thyme in a small roasting pan. Place the mixture under the broiler for 5 or 6 minutes or until the vegetables begin to brown. Stir halfway through during the cooking time.

Build the Sandwich: Preheat a large saute pan over medium heat. Lightly brown one side of each bread slice and build the sandwich on the browned side of one slice. Lay a slice of provolone cheese on the bread. Spread mustard on the cheese, and then spoon the roasted vegetables onto the cheese. Place the slice of Jack cheese on the vegetables and then top the sandwich with the brown side of the bread facing the inside of the sandwich.

Grill the Sandwich: Spread a little butter on one side of the sandwich, then place the sandwich, butter side down, onto the pan. Spread a little butter on top of the sandwich. Grill for 1 to 2 minutes or until browned. Flip the sandwich and grill for another 1 to 2 minutes until brown.