1 ¼ cups fresh baby spinach
1 ½ cups marinara sauce
1 ounce sun-dried tomatoes (not in oil), diced (about ¼ cup)
¾ cup shredded part-skim mozzarella cheese
2 tbsp. grated Parmesan cheese
12 ounces (large) cheese ravioli
Heat oven to 425ºF. Put spinach in a colander in the sink. Mix marinara sauce and sun-dried tomatoes together in a large bowl. In a smaller bowl, combine mozzarella and Parmesan.
Bring a large pot of salted water to a boil. Add ravioli and cook just until they float to the surface, 1 to 2 minutes. Drain ravioli over spinach to wilt. Add ravioli and spinach to marinara mixture. Lay down enough ravioli to cover the bottom of a 9- by 1 ½-inch gratin dish (or bake in individual 4 ½- to 5-inch gratin dishes). Sprinkle 1/3 of the cheese mixture on top. Repeat with remaining ravioli and cheese mixtures, finishing with the cheese on top. Bake until hot and bubbly throughout, 10 to 12 minutes. Serves: 4.