|1 tbsp vegetable oil|
|1 cup finely chopped onion|
|4 garlic cloves • finely chopped|
|1 tbsp tomato paste|
|1 28 oz. can whole tomatoes|
| 1 sprig basil plus ¼ cup chopped, divided|
|8 lasagna sheets|
|8 oz spinach|
|15 oz part-skim ricotta|
|1 cup parmigiano reggiano|
Preheat oven to 350ºF. To make the sauce, place a large saucepan over medium heat. Add the vegetable oil and sauté the onion, seasoning with a little salt and pepper, until softened and starting to brown, about 2 minutes. Add the garlic and tomato paste, and stir to allow the tomato paste to caramelize, about 1 minute. Add the tomatoes, breaking them up with a fork or whisk, and the sprig of basil. Simmer for 20 minutes. Remove basil before assembling rotolo.
Bring a large pot of salted water to the boil. Cook the lasagna according to package directions. Drain and reserve.
While the sauce is simmering, place the spinach in a pan. Cover and wilt the spinach (add a couple of tablespoons of water to the pan if needed to help wilt). When the spinach is cool enough to handle, squeeze out excess water and finely chop. Place in a bowl with the ricotta, egg and remaining ¼ cup basil. Season with salt and pepper. Reserve.
To assemble the rotolo, place one lasagna noodle on a work surface. Spread about 1/3 cup (1/8 of the spinach mixture) along the noodle. Roll up the noodle and repeat with remaining filling. Ladle about ½ cup of the tomato sauce along the bottom of an oven-proof dish. Place the noodles in the pan, seam side down, and cover with remaining sauce. Sprinkle with the Parmigiano. Place in the oven and bake until heated through, about 30 minutes. To serve, place 2 rotolo on a plate.