Mushroom Fettucine Florentine

12 ounces fettuccine
2 tablespoons olive oil
1 pound fresh white mushrooms, thickly sliced, about 5 cups
1 cup diced onion
1 teaspoon salt
1/2 teaspoon ground black pepper
1 (9-ounce) package frozen creamed spinach, thawed
1 cup diced fresh plum tomatoes
1 1/2 cups diced fontina cheese

1. Cook pasta in salted water according to package directions; drain, reserving 1 cup pasta water. Place pasta in a large serving bowl; cover and set aside.

2. Meanwhile, in a large skillet, heat oil until hot. Add mushrooms, onion, salt and black pepper; cook until mushrooms are golden, about 5 to 7 minutes.

3. Stir in creamed spinach and tomatoes; cook until tomatoes are heated through, about 3 minutes. Spoon over reserved pasta. Sprinkle with fontina; toss to coat, adding reserved pasta water to achieve a creamy consistency. Serve immediately.