Bring a large pot of salted water to a boil.
Heat 4 tbsp olive oil in a large skillet over medium heat. Add the sausage and cook, breaking up the meat with the back of a wooden spoon until browned - about 3-5 minutes.
Add the scallion whites, pressed garlic and rosemary and cook for a couple of minutes, until the scallions begin to wilt.
Add the two cans of tomatoes with their juices , 1 cup of the boiling water and sugar, salt and pepper. Let the sauce simmer while you cook the pasta.
Add the pasta to the boiling water and cook as the label instructs for al dente. Reserve 1 cup of cooking water, then strain the pasta.
Add the cooked pasta to the tomato sauce along with the fresh chopped spinach and half of the scallion greens. Toss to coat the pasta and wilt the spinach, about 1 minute, gradually adding the reserved pasta water as needed to loosen. Remove from the heat.
Sprinkle the cheese over the pasta and toss well. Serve the pasta with the remaining scallion greens sprinkled on top.