Preheat the oven to 350°F. Spray a 13 x 9 inch baking dish with cooking spray. Set aside.
In a large skillet cook ground beef and onion in a few drizzles of olive oil over medium-high heat. Cook until beef is browned and no pink remains. Drain excess fat from pan.
To the beef add tomatoes, tomato sauce, tomato paste, Italian seasoning, salt and pepper flakes. Simmer on medium-low, uncovered for 10 minutes then remove from heat and stir in pepperoni.
Meanwhile, cook noodles in salted water per package directions. Drain well.
Return noodles to pot and onto burner with heat off. To the noodles add cream cheese and half and half. Mix until cream cheese has melted. Add Parmesan, mix well.
To assemble: Layer ½ noodles on bottom of baking dish. Top with ½ sauce and ½ cheese. Repeat ending with cheese.
Bake for 35-45 minutes or until bubbly and cheese is lightly browned.
Let stand for 10 minutes. Garnish with chopped parsley just before serving.