Wash the sweet potato in water, then cut in half and microwave for 5 minutes (I use a 600 W microwave).
Then, wrap it in foil, and bake it in the oven for 30 minutes at 200 ℃.
After 30 minutes, test with a skewer. If it has softened, it's complete. If it's still hard, bake it a little longer.
The foil will stick to the potato, so let it cool off a bit before removing the foil ^^
Story Behind this Recipe
Sweet potatoes tend to lose their sweetness in the microwave or a steamer, but relying on the oven alone takes time... So, I came up with this combination technique. I tried it many times and finally found the right timing.
Since all it takes is microwaving and baking in the oven, I don't have any hints in particular (lol). They're done once they've softened ^^ If the potato you're using isn't that big, there's no need to cut it.