Cheesy Tortellini Casserole

Ingredients

• 1 1/2 pounds prepared frozen cheese tortellini
• Salt
• 12 ounces cremini or white button mushrooms, roughly chopped or sliced into 1/4-inch slices
• 1 tablespoon butter
• 3 cloves garlic, minced
• 1 28-ounce can crushed tomatoes
• 1 large bunch Swiss chard, ribs removed, leaves chopped , OR 2 cups fresh chopped spinach, OR 1/2 cup frozen spinach
• 1 1/2 teaspoons dried basil, or 1 tablespoon finely chopped fresh basil
• 1/4 teaspoon fennel seeds, crushed
• Pinch of red pepper flakes
• 1/2 cup grated Parmesan cheese
• 4 to 6 ounces Mozzarella cheese slices, enough to cover the surface of the casserole

Directions

1. Heat the oven to 400 degrees F. Pour 3 quarts of water into a large pot, add 1 1/2 tablespoons of salt, and set it over high heat. When it boils, drop in the tortellini. After the pot comes back up to a boil, let the pasta cook 2 minutes longer, just to al dente. You want it a little firm, since the casserole gives it more time in the oven. Take the pot off the heat, drain the tortellini, and set it aside.
2. While the pasta is cooking, get the sauce going. Place a large, heavy-bottomed nonstick pan, hard anodized aluminum or cast iron if you have it, over medium heat. Add the mushrooms and cook them dry, with no fat in the pan, for 5 to 10 minutes. As they warm, they will give off liquid and cook in that. When the mushrooms are coated in their own juices, stir in 1 tablespoon butter.
3. Add the garlic, crushed fennel seeds, and red pepper flakes to the mushrooms, and cook for 1 minute more. Stir in the crushed tomatoes and the dried or fresh basil. Raise the heat until the sauce simmers, then turn it down so it stays at a gentle simmer for 5 minutes. Add the chopped chard and cook for 5 more minutes, until it starts to wilt. Stir in the grated Parmesan cheese, then add 1/2 teaspoon of salt, adjusting more or less to taste.
4. Stir the cooked tortellini into the sauce, then take the pan off the heat. Spoon the mixture into a 9x13 casserole dish and smooth it into an even layer. Lay the sliced Mozzarella over the tortellini to cover the top.
5. Cover the dish with foil. Keep the foil from touching the cheese, or lightly rub the underside with a little olive oil so the cheese does not stick as it cooks; nonstick foil works too. Bake at 400 degrees F for 20 minutes. Take off the foil and broil for 4 to 5 minutes more, until the top is lightly browned and bubbling.