Heat the oven to 375°F and grease a 9-by-13-inch baking dish.
Boil the macaroni in salted water for 2 minutes less than the package directs, drain it and return it to the pot.
Brown the beef and onion in a large skillet over medium-high heat for 7 to 9 minutes, breaking up the meat, until the beef reaches 160°F, then drain well.
Stir in the tomato paste, tomato sauce, broth, mustard, paprika, salt and pepper and simmer for 3 minutes.
Combine the sauce, macaroni, pickles and 1 cup cheddar, then spread the mixture in the prepared dish and top with the remaining cheddar.
Bake uncovered for 20 to 25 minutes, until the edges bubble and the cheese has browned in spots.
Rest for 5 minutes before serving so each scoop holds together.
