In a skillet, cook the onion and garlic until the onion is soft. Add a bit of water if it sticks. Fold the cooked onion, sweet potato and greens into the tofu mixture. Pour into an oiled pie plate or ovenproof skillet. Bake at 375° for 35 minutes or until the center is firm and the top lightly browned. Let rest on the counter 5-10 minutes before cutting.