Cook pasta according to package directions. When it is done cooking, drain water then stir in 2 cups of pasta sauce
Heat 1 Tablespoon olive oil in large skillet over medium heat. Saute yellow onion until it's just about done. Add in Italian sausage/ground beef and continue cooking until the meat is cooked through. Drain excess fat. Stir in 1 teaspoon oregano, 1/2 teaspoon red pepper flake, and 3/4 teaspoon garlic powder. Stir in remaining 3 cups of pasta sauce and simmer for about 10 minutes.
Spray 9x13 casserole dish with non stick spray. Arrange the pasta that you tossed with sauce in the bottom of the pan.
In a small bowl combine softened cream cheese, sour cream, and most of the scallions (reserve a few for garnish) and 1 teaspoon of Italian seasoning.
Drop spoonfuls of this cheesy mixture on top of the pasta, then use a spatula to spread it evenly over the pasta.
Pour the meat sauce mixture over the cheese layer, then top with 1 1/2 cups of cheddar cheese and 1 cup of Monterrey jack cheese. Bake for 30 minutes or until the cheese is bubbly delicious. Let sit for about 5 mins before cutting and don't forget to sprinkle the remaining scallions on top