Lasagna

Ingredients

For the sauce

• 1 tbsp olive oil
• 1 lb sweet Italian sausage, casings removed
• 1 lb ground beef, 85% lean
• 1 medium yellow onion, finely chopped
• 4 cloves garlic, minced
• 2 tbsp tomato paste
• 1 tsp dried oregano
• ¼ tsp red pepper flakes
• 1 can crushed tomatoes, 28 oz
• 1 can tomato sauce, 15 oz
• 1 cup water
• 2 tsp Diamond Crystal kosher salt
• 1 tsp sugar, if the tomatoes taste sharp (optional)
• 1 handful fresh basil leaves, torn

For the ricotta layer

• 15 oz whole-milk ricotta
• 1 large egg
• 2 oz Parmesan, finely grated, about 1 cup, divided
• ¼ cup parsley, chopped
• ½ tsp black pepper

To assemble

• 12 no-boil lasagna noodles, from a 9 oz box
• 1 lb low-moisture whole-milk mozzarella, shredded, about 4 cups

The salt amounts here are for Diamond Crystal kosher salt. If you have Morton kosher salt, use a little over half as much, because its grains are denser and saltier by the spoon.

Steps

1. Heat the oil in a large Dutch oven over medium-high heat. Add the sausage and beef and break them up with a spoon, then leave them alone for a few minutes at a time so they brown rather than steam. Cook until no pink remains and there are dark brown bits on the bottom of the pot, 10 to 12 minutes.
2. Add the onion and cook until soft, about 5 minutes. Stir in the garlic, tomato paste, oregano and red pepper flakes and cook until the paste darkens to brick red, about 2 minutes.
3. Add the crushed tomatoes, tomato sauce, water and salt and scrape up the bottom. Bring to a simmer, partly cover, and cook, stirring now and then, for 30 minutes. It should be looser than a pasta sauce, like a thick soup; no-boil noodles drink a lot. Taste, add the sugar if it is sharp, and stir in the basil.
4. While the sauce simmers, heat the oven to 375°F. Stir together the ricotta, egg, half the Parmesan, the parsley and the pepper.
5. Spread about a fifth of the sauce over the bottom of a 9 x 13 inch baking dish. Lay 3 noodles on top; they won't cover every inch and will expand as they bake. Dollop a third of the ricotta mixture over and spread it out, then scatter over a quarter of the mozzarella and spoon over another fifth of the sauce. Repeat twice more.
6. Finish with the last 3 noodles and the remaining sauce, covering every edge of pasta, since any that stays dry bakes hard. Top with the rest of the mozzarella and Parmesan.
7. Oil a sheet of foil and cover the dish, oiled side down. Set it on a sheet pan and bake 40 minutes. Uncover and bake until the top is spotted brown and the edges bubble hard, 15 to 20 minutes more. A knife should slide through the middle with no resistance from the noodles.
8. Rest the lasagna on a rack for 20 minutes before cutting.

Notes

To make ahead, assemble, cover and refrigerate up to 2 days, then bake straight from the fridge with 10 more minutes under foil. To freeze, wrap the unbaked dish well and freeze up to 3 months; thaw overnight in the fridge before baking. Baked leftovers keep 4 days and reheat well by the slice. With regular noodles, boil 12 until just bendable and cut the water from the sauce. For a half batch in an 8-inch square dish, beat the egg and use half.