Prepare the oven and pan. Heat the oven to 350°F. Lightly coat a 9x13-inch baking dish with nonstick cooking spray and set it aside.

Cook the beef and onion. Place the ground beef and chopped onion in a large skillet over medium-high heat. Cook for about 10 minutes, breaking the beef into crumbles, until the meat is browned and the onion has softened.

Add the garlic. Drain away any excess grease from the skillet. Stir in the minced garlic and cook for about 1 minute, just until aromatic.

Finish the meat sauce. Pour in the tomato sauce and add the Italian seasoning. Reduce the heat and let the mixture gently simmer for about 5 minutes, stirring occasionally, then season with salt and pepper and remove from the heat.

Cook the egg noodles. Meanwhile, bring a large pot of salted water to a boil and cook the egg noodles according to the package directions, stopping when they are just al dente. Drain the noodles thoroughly.

Make the creamy noodle mixture. Combine the sour cream and cottage cheese in a large bowl. Add the drained noodles, season lightly with salt and pepper, and gently toss until the noodles are evenly coated.

Assemble the casserole. Spread half of the creamy noodle mixture across the bottom of the prepared baking dish. Spoon half of the beef sauce over the noodles, then repeat with the remaining noodles and remaining meat sauce.

Add the cheese. Sprinkle the grated cheddar evenly over the entire casserole.

Bake. Bake uncovered for about 30 minutes, or until the casserole is bubbling around the edges and the cheddar is completely melted.

Rest before serving. Remove the casserole from the oven and let it stand for 10 minutes before scooping and serving.