Cut kabocha in half. Remove stem (if present) and scoop out seeds and pulp. Cut squash into several smaller wedges.
Bring a small amount of water to boil in a steamer pot (or similar arrangement for steaming vegetables). Add kabocha to steamer basket. Cover and cook 15 minutes, or until very soft.
Remove squash from heat and allow to cool. Once wedges are cool enough to handle, scoop flesh off of skins and into a large bowl. (Squash may be prepared up to 3 days in advance and stored in the refrigerator until ready to use).
Combine 1 ½ cups cooked squash with the rice milk in a blender or food processor, and blend until smooth. (Work in batches, if necessary). Pour into a medium mixing bowl.
Add arrowroot powder, baking powder, salt, eggs, melted ghee, sumac and ginger. Mix well. Allow the batter to stand for several minutes (it will thicken as it rests).
Heat a skillet or griddle over medium heat. Once it is fully hot, melt a small amount of ghee and coat the pan with it. Pour or spoon enough batter into pan to make pancakes of your desired size (we found that 4-5” pancakes were easiest to work with for this recipe, but feel free to go larger or smaller if you prefer).
Flip pancakes once bubbles form in the top surface and the batter starts looking slightly dry. Continue cooking until both sides are evenly browned and pancakes are cooked through (about 2 minutes per side). The cooked surfaces will darken very quickly – don't panic, they are not burnt! This batter simply cooks up to a much darker color than traditional flour-based recipes.