Start by preheating your oven to 350°F (175°C) so it's ready when your casserole is assembled.
In a large skillet, heat the olive oil over medium heat. Add the diced onion and minced garlic, sautéing for about 3-4 minutes until the onion is translucent and softened.
Incorporate the ground beef into the skillet, using a spatula to break it up into small pieces. Cook for approximately 5-7 minutes, until the beef is browned through. If there's excess fat, carefully drain it off.
Stir in the Worcestershire sauce, mustard, and season generously with salt and pepper. Mix everything together until well combined.
In a large pot, combine the elbow macaroni and beef broth. Bring this mixture to a rolling boil, then reduce the heat and let it simmer for about 7-8 minutes, or until the macaroni is tender but still al dente.
Gently fold in the halved cherry tomatoes, diced pickles, and half of the shredded cheddar cheese into the beef mixture, combining thoroughly.
Transfer this hearty beef and macaroni mixture into a greased 9x13 inch baking dish, spreading it evenly.
Sprinkle the remaining cheddar cheese evenly over the top of the casserole for that inviting cheesy crust.
Place the baking dish into the preheated oven and bake for 20-25 minutes, or until the cheese is bubbly and has turned a beautiful golden color.
When done baking, allow the casserole to rest for 5 minutes to set. Garnish with freshly chopped parsley before serving to add a pop of color and freshness.
Notes
Scoop portions onto plates or into bowls, ensuring some of the melted cheese and garnished parsley are visible for a fresh finish.