1. Set the Anova Sous Vide Precision Cooker to 131ºF (55ºC).

2. In a medium bowl, mix the sake, mirin, miso, and brown sugar. Add the cod and toss to coat.

3. Transfer cod and miso mixture to a large zipper lock or vacuum seal bag. Seal the bag using the water immersion technique or a vacuum sealer on the moist setting.

4. Place the bag in the water bath and set the timer for 30 minutes.

5. When the timer goes off, remove the bag from the water bath. Remove the cod from the bag and reserve the cooking liquid.

6. Heat chile oil in a large non-stick skillet over high heat. When the oil just begins to smoke, add the cod and sear until slightly blackened on one side, about 30 seconds. Transfer to a plate.

7. Return the skillet to medium-high heat and add the reserved cooking liquid. Bring to a rapid simmer and cook, stirring frequently, until reduced to a thick sauce.

8. Slice each cod fillet into 4 pieces and arrange on serving plates. Drizzle with reduced sauce and a few droplets of chile oil. Garnish with sliced chile and scallion. Serve.