To prepare tomato sauce: in a large saucepan, sauté onions and carrots until soft. Add minced beef and garlic and continue cooking until the meat is cooked. Add tomato paste, tomatoes and oregano and simmer over medium heat for 15-20 mins. Remove from the heat and set aside.
Meanwhile, prepare béchamel sauce by combining milk and MAGGI® Béchamel Mix in a medium saucepan. Bring to a boil and simmer over medium heat until slightly thick.
Arrange the rigatoni pasta in a round springform pan. Gently spoon tomato sauce on top to fill the inside of the pasta and pour béchamel sauce on top.
Sprinkle cheese on top and place in a preheated oven at 175°C for 20 mins until slightly golden on top.
Allow to cool for 5 mins before removing from the pan. Slice like a cake and serve.