Preheat oven to 375ºF.

Combine cream of mushroom soup, milk, Parmesan cheese, Italian seasoning and ½ teaspoon salt in a saucepan. Heat over medium heat until until the Parmesan cheese is melted, about 5 minutes. Remove from heat. Add the spinach; stir well to combine. Set aside.

Trim all fat from chicken breasts; pat dry. Cut each chicken breast into cubes. Melt 1 Tablespoon butter in a large frying pan. Add the chicken; and cook over medium heat until white on all sides, about 6 minutes. Remove chicken from pan; set aside.

In a large frying pan, add remaining 1 Tablespoon butter and olive oil. When the butter is melted, add onion and garlic; sauté over medium heat 5 minutes. Add mushrooms; increase the heat to medium high and cook the mushrooms until moisture has evaporated, about 5 minutes. Reduce the heat to medium; add the chicken, vermouth, lemon juice, remaining ¼ teaspoon salt and freshly ground pepper to taste. Cook over medium heat 5 minutes. Add the spinach mixture; stir well to combine.

Pour the spinach mixture in a 2½ quart casserole dish. Bake at 375ºF for 20 minutes. Top with shredded swiss cheese and bake for an additional 10 minutes, or until bubbly and lightly browned. Yield: 6 servings.