Heat 1 tablespoon extra-virgin olive oil in Dutch oven over medium heat until shimmering. Add 1 finely chopped onion and 1 teaspoon table salt and cook, stirring occasionally, until onion is softened, about 5 minutes.

Add 1 pound turkey sausage (casings removed), 8 ounces ground turkey, and ½ teaspoon pepper and cook, breaking up meat with wooden spoon, until no longer pink, about 5 minutes.

Stir in 2 tablespoons tomato paste, 6 minced garlic cloves, 2 teaspoons lightly cracked fennel seeds, and ¼ teaspoon pepper flakes. Cook until fragrant, about 2 minutes.

Stir in 1 (28-ounce) can crushed tomatoes, 1 (15-ounce) can tomato sauce, and 1 tablespoon Italian seasoning and bring to simmer.

Reduce heat to low, cover, and simmer gently until slightly thickened, about 20 minutes. Season with salt and pepper to taste and remove from heat.

Meanwhile, lay 15 curly-edged lasagna noodles in broiler-safe 13 by 9-inch baking dish and cover with boiling water. Let noodles soak until pliable, about 15 minutes, separating noodles with tip of paring knife occasionally throughout soaking time to prevent sticking.

Drain noodles and set aside, patting noodles and now-empty dish dry. Adjust oven rack to middle position and heat oven to 400 degrees.

Combine 1 pound cottage cheese, 1½ cups shredded mozzarella cheese, ½ cup shredded fontina cheese, remaining ¼ teaspoon salt, and remaining ¼ teaspoon pepper in bowl; set aside. Combine remaining ½ cup mozzarella cheese and remaining ½ cup fontina cheese in separate bowl; set aside.

Spread 1½ cups meat sauce over bottom of now-empty dish. Place 5 noodles side by side over sauce (noodles may overlap slightly), then spread about ⅔ cup cottage cheese mixture over top. Repeat two more times with 1½ cups meat sauce, 5 more lasagna noodles, and ⅔ cup cottage cheese mixture, then top with remaining meat sauce. Sprinkle reserved mozzarella-fontina mixture evenly over top.

Spray sheet of aluminum foil with vegetable oil spray and cover lasagna. Bake until sauce is bubbling, about 25 minutes.

Remove lasagna from oven and heat broiler element. Discard foil. Broil until cheese is golden, about 3 minutes.

Let lasagna cool on wire rack for 15 minutes. Slice and serve.