Cook the pasta: Bring a large pot of salted water to a boil. Cook pasta until just shy of al dente (1–2 minutes less than package time). Drain and set aside.
Preheat the oven: Set to 375°F (190°C).
Lightly grease a 9x13-inch baking dish.
Brown the beef: Heat a large skillet over medium-high. Spray with olive oil or add 1 teaspoon oil. Add ground beef and cook, breaking it up, until lightly browned and mostly cooked, about 4–5 minutes.
Spoon off any excess fat if needed.
Sauté the veggies: Add onion, garlic, bell pepper, and mushrooms (or zucchini). Cook 4–5 minutes, stirring, until softened and most moisture cooks off.
Build the “burger” sauce: Stir in crushed tomatoes, tomato paste, mustard, ketchup, Worcestershire, smoked paprika, onion powder, salt, and pepper. If the mixture looks too thick, add 1/4 to 1/2 cup broth.
Simmer 2–3 minutes to marry the flavors. Taste and adjust salt and pepper.
Combine with pasta: Add cooked pasta, 1 cup of the cheese, and diced pickles to the skillet. Toss until everything is coated and the cheese begins to melt.
Assemble the casserole: Transfer to the prepared baking dish.
Smooth the top and sprinkle the remaining 1/2 cup cheese evenly over the surface.
Bake: Place in the oven for 12–15 minutes, until the cheese is melted and bubbling at the edges.
Finish and serve: Let rest 5 minutes. Garnish with parsley or chives and extra pickles if you like. Serve warm.