1 tablespoon extra-virgin olive oil
1 medium yellow onion, chopped
2 cloves garlic, minced
1 small zucchini, finely diced
1 small yellow squash, finely diced
Salt and freshly ground black pepper
15 ounces whole milk ricotta
1/2 cup Parmesan cheese, finely grated
1 large egg, beaten
3 tablespoons fresh flat-leaf parsley leaves, chopped
28 ounces canned whole peeled tomatoes (I prefer San Marzano)
1 teaspoon salt
1/4 teaspoon freshly ground black pepper
1/4 cup fresh basil leaves, chopped
1 pound lasagna noodles, cooked according to package instructions and drained
1½ cups mozzarella cheese, grated
1/4 cup Parmesan cheese, grated
For the Filling:
Heat the oil in a large skillet over medium heat. Add the onions and garlic and cook until softened, about 4 minutes. Add the zucchini, yellow squash, salt and pepper, and cook, stirring frequently, until the squash softens but is not mushy, about 4 minutes. Pour the mixture into a medium bowl and let cool.
Add the ricotta, Parmesan, egg, parsley, 1/2 teaspoon salt and 1/4 teaspoon pepper to the cooled vegetables. Stir to combine.
For the Tomato Sauce:
In a food processor, pulse the tomatoes with their juices until they are coarsely ground or chop the tomatoes by hand. Transfer them to a bowl, add the salt and pepper, then stir in the basil.
For the Lasagna Rolls:
Preheat the oven to 375°. Grease a 9-inch x 13-inch baking dish.
Spread about 1 cup of the tomato sauce on the bottom of the baking dish.
To create the rolls, spread each lasagna noodle with a layer of the ricotta mixture. Starting at one end, roll up the noodle. Repeat with the remaining lasagna noodles and ricotta mixture.
I like to set up an assembly line by spreading out all of the noodles on a sheet pan so I can do this quickly. Another tip to make it faster and less messy is to put the ricotta mixture in a large resealable plastic bag. Snip a large hole out of one corner of the bag with scissors and use the bag to pipe the mixture onto each noodle.
Place each lasagna roll, seam-side down, into the baking dish.
Spread the remaining sauce over the lasagna rolls. Top with the mozzarella cheese and remaining 1/4 cup Parmesan cheese. Bake until the sauce is bubbling and the cheese is melted, about 35 to 40 minutes. Let stand 10 minutes before serving.