I added more spinach to the sandwiches after I took the photo, but wanted you to be able to see the chicken and cheese. I used rotisserie chicken, but you can use leftover cooked chicken or cook some especially for the sandwiches. I used thyme, but you can use oregano or rosemary or whatever your favorite herb is.
Warm Chicken Sandwiches with Mushrooms, Spinach & Fontina
4 rosette rolls, halved horizontally
3 T. extra-virgin olive oil
12 oz. sliced white mushrooms
1/2 red onion, thinly sliced
3 garlic cloves, chopped
2 c. shredded roast chicken
2 t. thyme
Salt & pepper
Whole grain mustard 8 oz.
Fontina cheese, shredded, divided
1 (5-oz.) bag baby spinach, chopped
Preheat oven to 325°. Place rolls, cut side up, on cookie sheets and toast lightly. Set aside.
Drizzle olive oil in skillet and warm over medium heat. Add onion and mushrooms. Sauté until onions are translucent and mushrooms release juices. Add garlic and sauté for another minute. Add chicken to skillet. Drizzle balsamic vinegar to taste and season with thyme, salt and pepper.
Spread mustard on bottom half of each roll on a cookie sheet. Top with chicken/mushroom mixture and then cheese. Broil just until cheese melts. Top each with spinach and then roll top.