Artichoke Spinach Pasta Casserole

Directions

1Cook the pasta according to package directions. Reserve 1/2 cup of the cooking liquid, then drain the pasta.

2Meanwhile, heat the oil in a large skillet over medium heat. Add the onion and 1/2 tsp each salt and pepper and cook, covered, stirring occasionally, until tender, 8 to 10 minutes. Add the garlic and cook, stirring, for 1 minute.

3Heat broiler. In a large bowl, combine the sour cream, cream cheese, Parmesan, lemon zest and lemon juice; stir in the onion mixture.

4Add the pasta to the bowl and toss to coat. Stir in the spinach, artichokes and 1/4 cup of the cooking liquid (adding more liquid if the pasta seems dry). Fold in 1/2 cup mozzarella.

5Transfer the pasta mixture to a broiler-proof 2 1/2- to 3-qt casserole dish. Sprinkle with the remaining 1/2 cup mozzarella and broil until golden brown, 3 to 5 minutes.

6Make it ahead: Line the casserole dish with foil, leaving a 3-in. overhang on two sides. Fill the dish with the prepared pasta mixture and freeze until just firm, about 20 minutes. Using the overhangs, lift the pasta out of the dish in one piece. Wrap in plastic, then foil, and freeze for up to 2 months.

7To serve: Let thaw in the refrigerator, remove the foil and plastic, and transfer the pasta to a broiler-proof casserole dish. Reheat, covered, in a 375°F oven, about 20 minutes. Sprinkle with 1/2 cup mozzarella and broil as directed.