I discovered this recipe on the Internet, but tweaked it for my taste. My family loves spaghetti and I like to find different ways to make it. My father-in-law likes a drier spaghetti with a light sauce and the rest of the family loves to see and taste the sauce. I had tried baked spaghetti a few times before, but never thought of making it myself. The next recipe Baked Spaghetti II shows my version.
Bring a large pot of slightly salted water to a boil. Add spaghetti and cook for 8 to 10 minutes, or until al dente. Drain and set aside.
In a large skillet over medium-high heat,saute the onions,green peppers and ground beef.Once the beef is browned and the onions and peppers are softened,add the tomatoes, mushrooms and oregano. Simmer uncovered for 10 minutes.
Preheat oven to 350 degrees. Grease a 9x13 inch baking dish. Place half of the cooked spaghetti into prepared dish. Top with half of the meat mixture. Sprinkle with 1 cup of the mild cheddar cheese. Repeat. In a medium bowl, mix together cream of mushroom soup and water until smooth; pour over casserole. Sprinkle with Parmesan cheese.
Bake in preheated oven for 30 to 35 minutes. Let stand 10 minutes before serving.