Start by heating the oven to 350°F and coat a 9x13-inch baking dish with nonstick spray.
In a skillet set on medium-high, cook the ground beef with the chopped onion until the meat is browned and the onion softens, about 10 minutes.
Add the minced garlic and sauté for another minute to release its aroma.
Pour in the tomato sauce and sprinkle in the Italian seasoning, then simmer gently, stirring now and then, for 5 minutes. Season with salt and pepper, then remove from heat.
Meanwhile, boil the egg noodles in salted water following the package directions until tender. Drain and set aside.
In a large bowl, mix together the sour cream and cottage cheese. Fold in the drained noodles, seasoning with salt and pepper as needed.
Spoon half of the noodle mixture into the baking dish, then layer on half of the meat sauce.
Repeat the layers, finishing up with the remaining meat sauce on top.
Sprinkle the grated cheddar cheese evenly over everything and bake until the casserole bubbles and the cheese is melted and golden, around 30 minutes.
Allow the casserole to rest for 10 minutes before serving so the flavors meld nicely.
