A comforting and flavorful pasta dish combining tender beef, creamy cheese sauce, and perfectly cooked pasta.
Cook the pasta in a large pot of boiling salted water until al dente, then drain.
Adding a bit of olive oil to the boiling water can prevent the pasta from sticking.
In a skillet, sauté the chopped onion with a pinch of salt and pepper until softened.
Cook the onion over medium heat to avoid burning and achieve a sweet flavor.
Add the deli roast beef to the skillet and cook until heated through.
Shred the beef into smaller pieces for even distribution in the dish.
In a saucepan, melt the butter, then whisk in the flour to create a roux.
Cook the roux until it turns a light golden color to remove the raw flour taste.
Gradually add the milk to the roux, whisking constantly until the mixture thickens.
Warm the milk before adding it to the roux to prevent lumps.
Stir in the cheese until melted and smooth.
Remove the sauce from heat before adding the cheese to prevent it from becoming grainy.
Combine the cooked pasta, beef mixture, and cheese sauce in a baking dish.
Mix thoroughly to ensure the sauce coats all the pasta evenly.
Bake in a preheated oven at 350°F for 15 minutes.
Cover the dish with foil to prevent the top from drying out.
Garnish with fresh parsley before serving.
Chop the parsley finely for a more even distribution.