Not all casseroles are exciting, but "with the right ingredients, and lots of color and ooey, gooey creaminess, you can really revamp them," Giada de Laurentiis told TODAY Food.
Preheat the oven to 350°F. Lightly butter an 9 by 13 inch baking dish.
Bring a large pot of salted water to a boil over medium high heat. Add the pasta and cook for 10-12 minutes or until al dente. Drain well reserving 1 cup pasta water.
In a large skillet heat the olive oil over medium high heat. Add the shallots and cook for 1 minute or until fragrant and soft. Add the turkey and cook, breaking it apart with a wooden spoon until the meat is cooked through and beginning to brown. Season with 1/4 teaspoon salt and 1/8 teaspoon pepper.
In a large bowl toss together the cooked pasta and the pesto loosening with the pasta water as needed to coat the pasta. Spoon half of the pesto pasta on the bottom of the pan. Spoon the cooked turkey over the first layer of pasta. Sprinkle half of the Parmesan cheese over the turkey. Repeat layering with the remaining pesto pasta. Top with the marinara and remaining cheese. Dot the top with butter and bake until the gratin is heated through and golden brown around the edges, about 40 minutes.