In a large skillet over medium heat, add 1 pound of ground beef. Cook for about 5-7 minutes until browned, breaking it apart with a spatula. Once the beef is about halfway cooked, add 1 diced onion, continuing to sauté until the beef is fully browned and the onion is translucent. Drain excess fat if needed.

While the beef cooks, bring a large pot of salted water to a boil. Add 2 cups of macaroni and cook according to package instructions until al dente, approximately 7-10 minutes. Once cooked, drain the macaroni and set it aside, ensuring it's still firm, as it will continue to cook when added to the sauce.

In the same skillet used for the beef, melt 2 tablespoons of butter over medium-low heat. Add 2 minced garlic cloves and sauté for 1 minute until fragrant. Gradually whisk in 2 tablespoons of flour, cooking for about 1-2 minutes until lightly golden, then slowly add 2 cups of tomato sauce, stirring continuously. Let the mixture come to a simmer and thicken.

Once your sauce is at a gentle simmer, add the cooked macaroni to the skillet with the beef and sauce. Stir well to combine, ensuring the pasta is evenly coated in the rich, flavorful tomato mixture. Cook everything together for another 2-3 minutes to heat through and allow the flavors to meld beautifully.

Remove the skillet from heat and stir in 1 cup of shredded cheddar cheese until melted and creamy. If you desire a cheesier dish, feel free to add more cheese. Give it a good mix, and enjoy the delightful aroma of your homemade Beefaroni as it melds together.

Spoon your hearty Beefaroni into bowls, optionally topping with more cheese if desired. For an extra special touch, cover the skillet with a lid for 2-3 minutes to let the cheese melt beautifully before serving. Pair with a side salad or garlic bread for a complete meal.