Start by browning the ground beef along with the chopped onion in a large skillet over medium heat. Cook until the beef is nicely browned and the onion is tender.

Once the beef is ready, toss in the sliced carrots, celery, and frozen peas. Let them cook together until the veggies start to soften – about 5 minutes.

Stir in the cooked egg noodles, cream of mushroom soup, milk, and half of the shredded cheddar cheese. Mix everything together until it’s nice and creamy.

Transfer this mixture into a greased 9×13-inch baking dish, and sprinkle the remaining cheese on top.

Pop it into a preheated oven at 350°F and bake for about 25 to 30 minutes, or until the dish is bubbly and golden brown.