1.   Preheat oven to 400F. In medium bowl, combine ricotta, mozzarella, spinach, salt and pepper.
2.   On a lightly floured work surface, roll dough out into a 15-inch circle.
Spread cheese mixture over one half of the circle, to within 1 inch of the edge.  Lift the other side of dough and fold it over, forming a half-moon.  Pinch the edges together to seal.
3.   Transfer to a large baking sheet and sprinkle the top with the Parmesan. Bake until puffed up and golden brown, about 15-20 min. Let stand for 5 min before slicing crosswise into thick slices.  Serve with spaghetti sauce on the side.
Note:  I used Pillsbury's Pizza Dough in the "roll" can and just unfolded the dough, rather than rolling out dough.  Also, I've added 1/3 cup chopped pepperoni pieces to the spinach mixture and it was good!
From Robin Miller's Robin To The Rescue.