Taco Shells and Cheese

Name: Taco Shells and Cheese
Ingredients: Kosher salt; 1 pound small pasta shells; 2 tablespoons olive oil; 4 tablespoons butter; 1 pound ground beef; 2 teaspoons chili powder; 1 teaspoon ground cumin; 1 teaspoon onion powder; 1/2 teaspoon garlic powder; 1/2 teaspoon paprika; One 10-ounce can diced tomatoes and green chiles, such as Rotel; 1/2 cup hot water; Freshly ground black pepper; 2 cups milk, plus more if needed for thinning; 8 ounces processed cheese, such as Velveeta, diced; 2 1/2 cups grated Cheddar jack cheese; 1 teaspoon dried cilantro; Sour cream and jarred salsa, for serving, optional