Ingredients
1/4 cup olive oil, plus more for foil
1/2 cup all-purpose flour
2 garlic cloves, minced
6 cups whole milk
2 packages (10 ounces each) frozen chopped spinach, thawed and squeezed dry
1 package (10 ounces) frozen peas
1/2 pound carrots (4 to 5), halved lengthwise and thinly sliced
Coarse salt and ground pepper
1 container (15 ounces) part-skim ricotta (about 2 cups)
1 large egg
1 package (9 ounces) no-boil lasagna noodles (12 to 16 noodles)
1 pound part-skim mozzarella, shredded
1 cup grated Parmesan
Preparation
Preheat oven to 400 degrees. In a large saucepan, heat oil over medium; add flour and garlic. Cook, stirring constantly, 2 to 3 minutes (do not let flour mixture darken); whisk in milk. Bring to a boil; reduce to a simmer, and cook, whisking occasionally, until thickened, 3 to 5 minutes. Add spinach, peas, and carrots; season with salt and pepper. Set sauce aside.
In a medium bowl, combine ricotta, egg, 1/2 teaspoon salt, and teaspoon pepper.
In the bottom of a 9-by-13-inch baking dish, spread a thin layer of vegetable sauce. Layer noodles, half the remaining vegetable sauce, another noodles, half the ricotta mixture, half the mozzarella, and half the Parmesan; repeat.
Cover dish with lightly oiled aluminum foil, and place on a large rimmed baking sheet. Bake 45 minutes, uncover, and bake until bubbling and browned, about 20 minutes more. Let cool 10 to 15 minutes before serving.
