Start by gathering all of your ingredients. This makes the whole process smoother. Chop your onion and bell pepper, and mince the garlic. Take a moment to measure out each ingredient. This is the building block of a successful casserole.

In a large skillet over medium heat, melt the salted butter. Add in the ground beef, cooking until it browns, about 5-7 minutes. Break it up with a wooden spoon as it cooks to achieve even browning. Once cooked, drain any excess fat from the skillet.

To your cooked beef, add the onion and green bell pepper. Cook this mixture until the veggies soften, approximately 3-4 minutes. Then, stir in the minced garlic, smoked paprika, and red pepper flakes. Allow the aroma of the spices to fill your kitchen for about a minute.

Pour in 32 ounces of savory beef broth and the same amount of filtered water. Bring this mixture to a boil, then add in your petite shell pasta. Stir well, and reduce the heat to a simmer. Allow this to cook according to the pasta's package instructions until al dente, usually about 7-9 minutes.

Before draining the pasta, be sure to set aside the 1/2 cup of starchy pasta cooking water. This adds richness to your casserole.

Once the pasta is done, remove the skillet from heat. Stir in the creamy cheese spread until completely melted, followed by the reserved pasta water. Mix in the shredded mozzarella cheese until everything is nicely combined.

Preheat your oven to 350°F (175°C). Grease a large casserole dish. Transfer the mixture from the skillet into the dish, spreading it out evenly. Top with slices of aged provolone cheese, ensuring complete coverage.

Pop the casserole into your preheated oven and let it bake for 20-25 minutes, or until the cheese is bubbly and golden brown. The smell wafting through your house during this time is just a bonus.

Once baked, remove the casserole from the oven. Allow it to cool slightly before serving. Enjoy it with your chosen sides, and don’t be surprised if everyone asks for seconds!