Lasagne Bolognese with Spinach - olive oil

Method

• Heat oil in a 12-to 14-inch heavy skillet over medium heat until it shimmers.
• Cook pancetta, onion, carrot, celery, and garlic, stirring occasionally, until vegetables are golden and softened, 12 to 15 minutes.
• Add beef and cook, stirring occasionally and breaking up any lumps, until meat is no longer pink, 6 to 10 minutes.
• Stir in wine, milk, tomato paste, thyme, 1/4 teaspoon salt, and 3/4 teaspoon pepper.
• Simmer, uncovered, stirring occasionally, until most of liquid has evaporated but sauce is still moist, about 1 hour.
• Put spinach in a kitchen towel (not terry cloth) and twist to squeeze out as much moisture as possible.
• Whisk together ricotta, eggs, parmesan, nutmeg, 1 1/4 teaspoons salt, and 1 teaspoon pepper.
• Transfer 1 1/2 cups ricotta mixture to another bowl and whisk in 1/4 cup milk; set aside.
• Whisk spinach into remaining filling with remaining 1/2 cup milk.
• Preheat oven to 375F with rack in middle.
• Soak noodles in a bowl of very warm water until pliable but not softened, 3 to 5 minutes.
• Place on a kitchen towel (it's not necessary to pat noodles dry).
• Spread 1 1/2 cups bolognese sauce in baking pan and sprinkle with 1 tablespoon parmesan.
• Cover with 3 noodles, leaving space in between.
• Spread half of spinach filling on top, then 1 cup bolognese sauce, and top with 1 tablespoon parmesan and 3 noodles; repeat.
• Top with remaining bolognese sauce, 1 tablespoon parmesan, and remaining 3 noodles.
• Pour reserved ricotta mixture over top and sprinkle with remaining 1/4 cup parmesan.
• Cover pan tightly with parchment paper and foil (or just buttered foil) and bake 50 minutes.
• Remove foil and bake until top is browned in spots, about 15 minutes more.
• Let stand 15 to 30 minutes before cutting.