Cheesy and Creamy Chicken Tetrazzini
1 cup chicken broth 1 pinch dried thyme, or to taste 1 pinch salt and ground black pepper to taste 1 tablespoon olive oil 1 ½ tablespoons margarine 10 tablespoons shredded Cheddar cheese, divid… 10 tablespoons shredded Swiss cheese, divided 2 cloves garlic, minced 2 skinless, boneless chicken breast halves, c… 2 tablespoons all-purpose flour 6 tablespoons shredded Parmesan cheese, divid… cooking spray ½ cup sliced mushrooms ½ pound fettuccine pasta ½ red bell pepper, cubed ½ small onion, finely chopped ¾ cup heavy whipping cream ¾ cup milk