Heat a large skillet or Dutch oven over medium-high heat. Add the ground beef and diced onion and cook, breaking the meat apart with a spatula, until fully browned and the onion is softened, about 6 to 8 minutes. Drain excess fat, leaving about 1 teaspoon in the pan.

Add the minced garlic, Italian seasoning, smoked paprika, salt, and pepper. Stir and cook for 1 minute until the garlic is fragrant.

Pour in the tomato sauce and beef broth, then add the dry pasta shells. Stir to combine and bring the mixture to a boil over medium-high heat.

Reduce heat to low, cover the pan, and simmer for 10 to 12 minutes, stirring occasionally, until the pasta is tender and most of the liquid has been absorbed.

Remove the lid and reduce heat to the lowest setting. Stir in the heavy cream, then add the shredded cheese in two to three additions, stirring between each until fully melted and the sauce is smooth.

Taste and adjust seasoning. Garnish with fresh parsley and serve immediately.