Cod is a delightful fish that we have often – we usually get it in our monthly Butcher?s Box subscription. The white fish is sturdy yet delicate and takes on the flavors of sauces well. This Keto Miso Cod recipe, inspired by the famed Nobu, is a favorite in our home ? though it takes a bit of planning because ideally, you want to marinade the cod in the sake mixture for at least a day beforehand – possibly even two!
I love this keto miso cod dish with baby bok choy because the flavor is perfectly absorbed by the bok choy and the texture of the crisp base and softened tip is a perfect combination for the tender fish filet. If I’m hungry, I also toss some shirataki noodles in with the baby bok choy as well.?
I prefer using white miso paste for this recipe, however in the photo, I actually used red miso paste because that?s all that was available at the market. It still turned out delicious, however the white miso flavor is a bit milder which I find works better with fish.?
This keto fish recipe also works well with salmon if you can’t find cod or prefer salmon.

Keto Miso Cod
Ingredients
FOR THE MARINADE
- 1/4 cup sake
- 1/4 cup mirin
- 1/4 cup white miso paste
- 3 tablespoons granulated Swerve or your preferred sweetener
- 4 black cod fillets 8 oz each
FOR THE FULL RECIPE
- 1 stalk baby bok choy
- 1 tablespoon toasted sesame oil
Instructions
- Two days before, make the marinade: bring the sake and mirin to a boil in a small saucepan over high heat.
- As soon as it starts to boil, turn the heat down to low and add the miso paste.
- Whisk until smooth.
- Add the sweetener and increase the heat, whisking constantly until the sweetener dissolves. Once smooth, remove from heat.
- Cool the marinade completely before pouring over the fish.
- Once cool, arrange the fillets in a baking dish and cover with marinade.
- Cover tightly and place in fridge at least overnight - ideally two days.
- When ready to cook, preheat over to 400?.
- Put a cast iron or oven-safe skillet over high heat on your stove.
- Spray skillet with a bit of avocado or olive oil and add the cod fillets, skin side up. Cook for about 3 - 4 minutes until bottom of fillet starts to brown.
- Flip and cook for another 3 - 4 minutes.
- Arrange baby bok choy around fillets and transfer to your preheated oven for 8 minutes ? until the fish is opaque and bok choy is wilted.
- Remove from oven and drizzle toasted sesame oil over the fish and vegetables.