Preheat the oven to 350 degrees F. Spray an 9 x 13 glass pan with cooking spray.
Cook the tortellini in a large pot of boiling water until just tender, about 2 minutes. Drain. Add the tortellini to the pan and add your sauce and parsley. Mix carefully until the noodles are covered in marinara sauce.
Top the mixture with cheese.
Sprinkle green onions on top. Cover and bake until the sauce bubbles and the cheeses on top melt, about 30 minutes.