Preheat oven to 350°F (175°C). Lightly grease a casserole dish.

Cook 2 cups of elbow macaroni according to package instructions until al dente, drain and set aside.

In a large skillet, brown 1 pound ground beef over medium heat until fully cooked, breaking it apart with a spoon. Drain excess fat.

Add 1 small chopped onion and 1 clove minced garlic to the beef and sauté for 3-4 minutes until softened.

In a medium saucepan, melt 3 tablespoons butter over medium heat. Stir in 3 tablespoons all-purpose flour to form a roux and cook for 1-2 minutes, whisking constantly.

Gradually whisk in 2 cups milk, stirring continuously until sauce thickens (about 5-7 minutes).

Remove sauce from heat and stir in 2 cups shredded cheddar cheese until fully melted and smooth. Season with 1/2 teaspoon salt and 1/4 teaspoon black pepper.

Combine cooked macaroni, beef mixture, and cheese sauce in a large bowl and mix well.

Pour mixture into the prepared casserole dish and spread evenly.

Sprinkle an additional 1 cup shredded cheddar cheese evenly over the top.

Bake uncovered for 25-30 minutes until bubbly and golden brown on top.

Let cool for 5 minutes before serving. Enjoy!