Preheat oven to 375°F. Lightly grease a 2-quart glass casserole dish with coconut oil. Bring enough water in a large saucepan to a boil to cover sweet potatoes completely, and add the sweet potatoes. Reduce the heat, and simmer for about 30 minutes, or until softened.

Place the drained sweet potato in a large mixing bowl; mash lightly. Add the almond milk. Blend the potato mixture with an electric hand mixer set to medium until smooth and fluffy, about 2 minutes. Season with salt and pepper. Set aside.

Heat the 2 Tbs. of vegetable broth in a large skillet over medium heat. Cook the onion over medium-low heat until translucent, then add the garlic and cook for another minute. Add the celery, carrot, peas, corn, thyme, and rosemary. Increase the heat to medium-high.

Pour the rest of the vegetable stock into the skillet. In a small bowl whisk together the almond milk and arrowroot until smooth. When the vegetable stock and mixture begins to boil, reduce the heat. Add the arrowroot mixture, and whisk until the lumps disappear. Add the sea salt and black pepper, and season to taste. Remove from heat. Stir in the egg replacer and water combination. Pour the veggie mixture into the bottom of the prepared casserole dish, spreading it evenly across the bottom. Spoon the potato mixture over the vegetables, spreading to cover all the way to the edges of the dish. Sprinkle the top with nutmeg, if desired.

Bake in preheated oven until top is slightly browned, about 40 minutes. Allow to rest 20 minutes or more before serving.