Brown the lean ground beef in butter in a large skillet over medium heat.

Drain any excess grease from the skillet.

Stir in the tomato sauce to the browned beef.

Simmer the beef and tomato sauce mixture for 5 minutes, stirring occasionally.

Bring a pot of salted water to a boil.

Add the wide egg noodles to the boiling water and cook for 10 minutes, or until al dente.

Drain the cooked noodles thoroughly.

Preheat oven to 350°F (175°C).

In a large bowl, combine the cottage cheese, softened cream cheese, sour cream, chopped green onion, and chopped bell peppers.

Mix well until the cheese mixture is smooth and evenly combined.

Lightly butter a 2-quart round, deep casserole dish.

Spread half of the drained noodles evenly in the bottom of the prepared casserole dish.

Cover the noodles with the entire cheese mixture, spreading it evenly.

Top the cheese mixture with the remaining noodles.

Pour the melted butter evenly over the top layer of noodles.

Spread the meat sauce evenly over the noodles and butter.

Bake in the preheated oven for 30 minutes, or until heated through and bubbly.

Let the casserole stand for a few minutes before serving.