Skinny Cheeseburger Casserole

Preheat the oven to 350º. Bring a large pot of salted water to a boil, add the pasta, and cook until al dente. Drain and set aside. Meanwhile, in a 12-inch ovenproof skillet over medium-high heat, heat oil. Add the onion and garlic and sauté, stirring, until fragrant, 1 minute. Add the turkey and steak seasoning. Cook, stirring frequently, until the turkey is browned on the edges (the turkey may not be completely cooked but will finish in the oven). Drain any accumulated juices. Add the canned diced tomatoes, tomato paste, mustard, and relish, then reduce heat to medium and stir until bubbling. Remove from heat and stir in drained pasta. Smooth the top. Cover the top of the casserole with cheese slices, cutting as necessary to fit. Bake until the cheese is melted and the mixture bubbles, 23 to 25 minutes. Garnish with diced tomatoes, sprinkle with salt and pepper, and serve.