This easy spinach lasagna recipe was designed so that you can assemble the pasta dish months in advance, stash it in the freezer, and then toss it straight into the oven on a weeknight when you don’t feel like cooking but still want to eat something homemade. (But, if you want to bake and eat it right away, that works too.) It starts with store-bought lasagna noodles that you don’t even have to boil. Important: Don’t make the mistake of buying “no-boil noodles” as these can turn mushy when cooked. The secret to achieving the ideal al dente texture here lies in the quick homemade marinara sauce, made with just enough liquid to cook the noodles through without leaving the baked casserole too watery.
The creamy ricotta cheese mixture layered throughout this vegetarian lasagna is fortified with cream cheese and heavy cream, ensuring a lush sauce that won’t dry out or turn grainy. We fold thawed frozen spinach into the ricotta mixture (make sure to drain it and press on the solids to remove excess water). If you don’t have spinach on hand, take this as an opportunity to use up whatever cooked vegetables you have left over, like grilled zucchini or sautéed mushrooms. Covering the lasagna with aluminum foil helps the comfort food classic cook evenly and keeps the top from drying out. But do uncover the dish and finish with a quick broil to achieve a burnished top enhanced by a shellac of Parmesan cheese.
In the mood for classic lasagna with layers of ground meat and béchamel? Check out BA’s Best Lasagna.
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cup extra-virgin olive oil, plus more for pan
garlic cloves, finely chopped
28-oz. can whole peeled tomatoes
tsp. crushed red pepper flakes
tsp. Diamond Crystal or 1 tsp. Morton kosher salt, divided
16-oz. package frozen chopped spinach, thawed, drained
16-oz. container whole-milk ricotta
oz. cream cheese, room temperature
oz. Parmesan, finely grated, plus more for serving
cups heavy cream
Freshly ground pepper
dried lasagna noodles (from a 16-oz. box; not no-boil)
Preheat oven to 375°. Grease a large 13×9″ baking dish with extra-virgin olive oil. Heat ¼ cup extra-virgin olive oil in a medium saucepan over medium. Add 5 garlic cloves, finely chopped, and cook, stirring, until beginning to brown around edges and fragrant, about 2 minutes. Add one 28-oz. can whole peeled tomatoes and ¼ tsp. crushed red pepper flakes and crush tomatoes with a wooden spoon to form a mostly smooth sauce. (If your tomatoes are on the firmer side, use kitchen shears or a potato masher to break up.) Season with 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt and cook until mixture is thickened and flavors have come together, 15–17 minutes. Transfer to a 4-cup heatproof measuring glass and, stirring constantly, pour in water to make 3 cups sauce.
Meanwhile, mix one 16-oz. package frozen chopped spinach, thawed, drained, one 16-oz. container whole-milk ricotta, 4 oz. cream cheese, room temperature, and 3 oz. Parmesan, finely grated, in a large bowl to combine, then mix in 1½ cups heavy cream. Season with freshly ground black pepper and add remaining 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt.
Pour a scant ½ cup tomato sauce into prepared baking dish and spread into a thin layer just to coat. Place 3 dried lasagna noodles in a single layer on top. Spread 1 cup spinach mixture over evenly. Pour ½ cup sauce on top and spread over evenly. Starting with another layer of noodles, repeat process to create 4 more layers. Sprinkle a thin layer of finely grated Parmesan on top and cover pan with foil.
If not making ahead, bake lasagna 45 minutes. Heat broiler. Uncover lasagna and broil until top is golden brown and bubbly, about 4 minutes.
Do ahead: Lasagna can be assembled 3 months ahead; cover tightly and freeze. Bake, covered, in a 375° oven 45 minutes. Uncover and bake 10 minutes more. Broil about 3 minutes.