Step 1

Preheat the oven to 350 degrees. Spray a 9 x 13 inch baking dish with cooking spray.

Step 2

In a large pot of boiling salted water, cook the pasta according to the package directions for al dente and drain well.

Step 3

Meanwhile, in a large skillet, heat the oil over medium-low heat. Add the onions and cook until soft, about 5 minutes. Stir in the garlic and cook for 30 seconds.

Step 4

Stir in the beef and cook until browned; season with salt and pepper.

Step 5

Stir in the tomato paste, then add the tomatoes and mustard. Let the mixture bubble gently until it is slightly thickened, about 2 minutes.

Step 6

Toss the meat mixture with the pasta and spread it into the prepared dish.

Step 7

Top with the cheddar and bake until the cheese is melted, about 15 minutes. Sprinkle the chopped pickles over the top and serve.