Carefully cut the squash in half lengthwise, then scoop out the seeds. Place the halves face down and cut in 1/4 inch thick slices ( thicker slices are more difficult to cook )
Remove and discard the stems from 1 bunch of kale or other greens. Chop the leaves roughly.
Dice 1 large onion and mince 3 cloves of garlic. Sauté the onion in 3 tbsp of oil until soft, then add the garlic and cook another minute. Add the kale and cook for 5 minutes. Season with salt and pepper.
Lightly grease an 11 or 13 by 9 inch baking dish. The amount of slices of squash will dictate your pan size. Cover the pan with an overlapping layer of squash slices . Sprinkle with salt and pepper.
Spread the cooked greens over the squash , then another layer of squash.
Spoon 2 cups of diced tomatoes and 1 tbsp chopped fresh sage leaves over this layer, then make another layer of squash. Top with grated cheese.
Bake the casserole at 350 degrees for 45 minutes or until the cheese on top has browned or is bubbling.