In a large cast-iron Dutch oven, heat oil over medium-high heat. Add beef, paprika, 1½ teaspoons salt, cumin, and pepper; cook until beef is browned and crumbly, about 5 minutes. Remove beef using a slotted spoon, reserving drippings in pot, and let drain on paper towels.
Add onion, bell pepper, and garlic to pot; cook until tender, about 5 minutes. Stir in flour and remaining 1½ teaspoons salt; cook for 1 minute. Whisk in milk until smooth. Stir in tomatoes; bring to a simmer. Reduce heat to medium; cook for 3 minutes. Gradually stir in cheese until melted. Stir in beef, cooked pasta, and oregano. Garnish with olives, oregano, cheese, and paprika, if desired.
Recipe by Southern Cast Iron at https://southerncastiron.com/spanish-mac-cheese/