The Best Spinach Lasagna Recipe

Name: The Best Spinach Lasagna Recipe
Cuisine: European, Mediterranean, Italian
Ingredients: 2 tablespoons butter, divided; 2 tablespoons extra-virgin olive oil; 1 shallot, finely minced (about 1/2 cup); 6 medium cloves garlic, minced (about 2 tablespoons); Kosher salt and freshly ground black pepper; 2 pounds fresh flat or curly spinach leaves, washed and dried; 2 pounds fresh ricotta cheese (see note); 2 eggs; 4 ounces finely grated Parmigiano-Reggiano cheese; 1 teaspoon freshly grated nutmeg; 4 tablespoons butter; 1/4 cup flour; 1 quart (4 cups) whole milk; 12 ounces grated low moisture mozzarella cheese; 12 ounces grated Comté, Gruyère, or Emmenthaler cheese; 1 1/2 pounds (enough sheets to make 12 layers) fresh lasagna noodles