In a medium skillet cook mushrooms in hot oil over medium heat for 3 to 5 minutes or until tender, stirring occasionally. Add shallots, thyme, garlic, and 1½ teaspoon salt; cook and stir for 1 minute more.
Remove from heat
Sprinkle chicken lightly with salt and pepper. Place in a baking pan. Spread chicken with pesto; top with mushroom mixture.
Bake for 30 to 35 minutes or until chicken is no longer pink. Top with cheese.
Bake for 3-5 minutes more until cheese is melted.
Serve, arrange chicken and mushrooms on a bed of spinach and a side of cooked linguine. Drizzle left- over sauce onto linguine.