1 large spaghetti squash (about 8 pounds total)
3 tablespoons olive oil
  Coarse or Kosher salt
  Freshly ground black pepper
4 cups grated mozzarella cheese (divided)
3/4 cup Parmesan cheese (divided)
1 tablespoon minced fresh garlic
2 pounds mixed leafy greens (such as chard, kale, collard greens or beet tops)
1/2 cup olive oil
2 tablespoons minced shallots
2 cups ricotta cheese
1 cup pesto
2 tablespoons chopped fresh Italian parsley