Heat a large Dutch oven or heavy-bottomed pot over medium-high heat. Add ground beef and start breaking it up with a wooden spoon.

When beef starts browning, add onion powder, garlic powder, and smoked paprika. Continue cooking until lightly browned, about 5 minutes.

Add diced onions and shredded carrots to the beef. Cook for 3-4 minutes until vegetables begin to soften and beef is fully browned.

Add minced garlic, stir and cook for 30 seconds until fragrant.

Sprinkle flour over the mixture and stir constantly for 1 minute to cook out the raw flour taste.

Gradually pour in beef broth while stirring constantly to prevent lumps. Add Worcestershire sauce and mustard powder.

Add shell pasta, bring to a simmer. Cook for 8-10 minutes, stirring occasionally to prevent pasta from sticking to bottom.

Reduce heat to low. Stir in milk and let warm through (don't let it boil).

Add cheeses gradually, stirring until each addition is melted before adding more.

Season to taste with salt and pepper. Garnish with fresh parsley if desired.