1/4 cup extra-virgin olive oil
1 pound ground chuck beef
Salt and pepper
1 1/2 pounds ricotta cheese
3 large eggs
1 pound lasagna sheets, cooked al dente
2 packages (10 ounces each) frozen chopped spinach, thawed and squeezed dry
3 cups shredded mozzarella
1/4 cup freshly grated Parmesan