Trim off ends of pumpkins and cut in half lengthwise. With a teaspoon scoop out seeds and part of the pulp leaving shells about 1 1/2 cm thick. Steam pumpkin over boiling water until crisp-tender (about 5 minutes). Plunge into cold water, drain well and set aside.
In a small frying pan over medium heat, melt one tablespoon of the butter. Add onion and garlic and cook until they are done. Squeeze the spinach to remove extra moisture and add to the garlic and onion and cook until thoroughly heated.
In a medium size mixing bowl, combine eggs, ricotta, Parmesan, parsley, salt, pepper, Italian seasoning and spinach mixture. Fill the pumpkin halves with this mixture and place in a shallow baking dish. Melt the remaining butter and brush over the pumpkin shells.
Bake for 20 minutes. If desired, serve with tomato sauce.