Scrub the sweet potato clean and pat it dry, then poke holes all over with a fork.
Wrap in aluminum foil and bake at 375°F for 40–50 minutes, until completely tender.
Make the topping: mix the room-temperature butter, miso, brown sugar and a splash of heavy cream until smooth and fluffy (you want it fluffy, not liquidy).
Cut the potato lengthwise down the center, stopping about an inch from each end, then squeeze both ends toward the middle to open it up.
Spoon the miso topping over the opened potato, then grate plenty of Parmesan over the top.
Brulee the top with a kitchen torch (or broil for about a minute) until caramelized and bubbling. Serve warm.
A sweet-and-savoury Friendsgiving/Thanksgiving side: roasted Japanese sweet potato, a fluffy miso-brown-sugar butter, and a snowfall of Parmesan torched to a brulee crust. Transcribed from @gwynethyuma's reel.
