Heat the oven. Preheat oven to 350°F. Coat two small cast iron skillets with olive oil.
Cook the pasta. Cook the pasta according to package directions for al dente pasta. Drain when pasta is done cooking.
Brown the ground beef. While the pasta is cooking heat a large skillet or saute pan over medium-high heat. Add the ground sirloin and onions; cook for 4-5 minutes until the ground sirloin is browned. Add the garlic and cook for an additional minute. Add the basil through pepper and cook for an additional minute until fragrant.
Make the meat sauce. Add the beef broth, wine and tomatoes; continue to cook until the mixture begins to boil. Reduce heat and simmer while you make the cheese sauce.
Make the roux. melt the butter in a small sauce pan over medium heat. Add the flour and whisk until a thick paste forms.
Make the cheese sauce. Slowly add the milk, a small amount at a time, stirring with a whisk after each addition until the sauce is smooth. Once all of the milk has been added cook for an additional 2-3 minutes, whisking constantly, until the sauce begins to thicken. Remove from heat and stir in the cheese; continue stirring until the sauce is smooth (sauce will be quite thick). Add the pepper and nutmeg; stir to combine.
Assemble and bake. Add half of the pasta to each of the prepared skillets. Top each skillet with half the meat sauce mixture then half of the cheese sauce. Bake for 15 minutes or until the cheese sauce begins to bubble around the edge of the skillet. Top with grated cheese and serve