2 cups kosher salt (preferably Diamond Crystal brand), divided
6 egg yolks
½ cup unfiltered apple cider vinegar
1 cup wood chips (preferably oak)
Directions
In an 8-inch square baking dish, sprinkle 1 cup of the kosher salt. Make 6 divots in the salt, each 2 inches apart, then place one egg yolk in each divot. Sprinkle the remaining cup of salt on top of the eggs, covering them completely. Cover with plastic and refrigerate for 2 days.
After curing, remove the egg yolks from the salt and rinse with apple cider vinegar. Place the yolks on a small wire rack set over a baking sheet and refrigerate, uncovered, for another 2 days, flipping the yolks after 1 day.
After drying, remove the tray of yolks from the refrigerator. Line a 12-inch cast-iron pan with tinfoil and place the wood chips over top. Heat the pan over medium heat until smoking heavily, 2 to 3 minutes. Place the wire rack with the yolks, uncovered, over the pan to smoke the yolks without cooking them, about 10 minutes.
Return the tray of yolks to the baking sheet and cover with cheesecloth. Let sit at room temperature until matured, 3 days more.
Grate the yolks as needed, keeping the rest in an airtight container in a cool, dry place for up to 1 month.