Warm the milk (90-110°F), mix in yeast and 1 tsp sugar, and let it activate (5 min).
In a stand mixer bowl, combine flour, sugar, salt, and nutmeg.
Add the activated yeast, tangzhong paste, eggs, and yolks.
Mix on low, then gradually add butter in small pieces.
Knead for 8-10 minutes until dough passes the "windowpane test."
Transfer to a greased bowl, cover, and let rise for 2 hours.
(Optional but recommended) Refrigerate for 24-48 hours for cold fermentation.