Preheat oven to 425 degrees F. Lightly spray a 13x9-inch baking dish with nonstick spray.
Place chicken cutlets in single layer on bottom of prepared pan.
In small bowl, mix together mascarpone cheese, spinach, and ranch seasoning until well combined. Spread over chicken.
Sprinkle shredded cheese on top of chicken, and top with tomato slices.
Bake chicken about 20-25 minutes or until cooked through and cheese is melted and browned around edges.
SNAPPY TIPS: Instead of chicken cutlets you can use boneless skinless chicken breasts but don't add the shredded cheese and tomato until the last 10 minutes of cooking since the thicker chicken will take longer to cook.SNAPPY SUBSTITUTIONS: Instead of ranch seasoning you can use your favorite seasoning mix. Instead of roma tomatoes, use your favorite tomato variety.