Halibut with Fermented Birch Leaf Sauce

Allison Hepworth - August 9, 2023

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Halibut with Fermented Birch Leaf Sauce 

Showcasing the best of the West Coast, our friend, Skipper Otto member and Chef Robin Kort has just published an amazing new cookbook entitled “The Coastal Forager’s Cookbook: Feasting Wild in the Pacific Northwest.”

Enclosed are 40 incredible recipes infused with Japanese, Italian and Spanish influences and she also shares tips on plant identification and guidance on mindful and sustainable foraging practices.

One of the delicious recipes is her Halibut with Fermented Birch, which Robin hopes inspires Skipper Otto members to increase their knowledge of what is locally abundant and edible, along with enjoying sustainable seafood!

Robin shares with us about this recipe: “Bright green birch leaves can be used much like green tea or as an herb to flavour dishes, the younger the leaf the better. Pour some boiling water over them and notice their fresh, slightly peppery aroma. They make a perfect complement to halibut or cod as a sauce. Think of them as similar to basil leaves.”


  • 1 cup (250 mL) young birch leaves (destem any older leaves)
  • 2 limes, zested
  • 1 large garlic clove, minced ½ tsp (2.5 mL) 
  • ½ cup salt (125 mL) 
  • lime juice (about 4 limes) 
  • 1 tsp (5 mL) fish sauce
  • 1 cup (250 mL) minced napa cabbage
  • ½ cup (125 mL) minced onion
  • 4 (each 8 oz/250 g) halibut fillets (about 1-inch/2.5 cm thick), skin on 
  • Kosher Salt
  • Grapeseed oil
  • 1 cup (250 mL) young birch leaves


Fermented Birch Leaf Sauce

  1. Put the birch leaves, lime zest, garlic, salt, lime juice, and fish sauce into a food processor and mince well.
  2. Transfer to a clean 4-cup (1 L) Mason jar and mix in the cabbage and onions.
  3. Drape a clean tea towel over the jar and leave to ferment for 3 days in a cool, dry cupboard.
  4. Drizzle in enough oil to cover the green sauce, then secure a lid on the jar and refrigerate.
  5. To store for a longer period, place scoops of the sauce into an ice-cube tray and freeze them, transfer to a resealable freezer-proof bag, and use as needed.

Fish Skin and Birch Leaves

  1. Take the fish out of the fridge, let stand 15 minutes.
  2. Line two baking trays with paper towel.
  3. Cut the skin from the flesh of the fish with a sharp knife if it’s still attached and pat dry. Slice the skin into ½-inch (1 cm) long pieces.
  4. Place ½ inch (1 cm) of the oil in a wide, deep pot or wok over medium heat and bring to 375°F. It should shimmer but not smoke.
  5. Fry the birch leaves until there are no bright green patches left, about 10 seconds, then remove to one of the prepared trays and dust with salt.
  6. Add the fish skin to the hot oil and cook until crispy, about 10 minutes.
  7. Remove to the remaining prepared tray to drain and then dust with salt.


  1. Preheat the oven to 170°F. Line a baking tray with a paper towel.
  2. Cut each fillet in half and pat dry. Season each side generously with salt.
  3. Keep the pot on medium and the oil at 375°F. Add each halibut fillet to the hot oil.
  4. Cook until golden brown, 4 minutes, then flip with tongs and cook for another 2–4 minutes, depending on fish thickness. Don’t overcook them!
  5. Transfer to the prepared tray to remove some of the excess cooking oil and then place in the warm oven while you fry the remaining fish.


  1. Serve each person 2 pieces of fish with a heaping tablespoon of sauce on the side.
  2. Top with crispy fish skin and fried birch leaves and a few fresh birch leaves for color.
  3. You can also serve this as a stand-alone appetizer for 8 people by splitting each fillet in half before you fry it.

Note: The key to success when you’re frying anything is keeping the oil hot, especially as you put your ingredients into it. Using a candy thermometer to make sure the oil stays at the right temperature is the easiest way to do this, but in this recipe you can also fry each piece of fish separately to help maintain 375°F throughout cooking. 

Servings: 4 people

Additional Wine Pairing Notes: A crisp white wine or rosé is a perfect pairing for this dish.

Recipe shared with us by our friend and member Chef Robin Kort of Swallow Tail Culinary Adventures.
Follow her on Instagram @swallowtailtours or find out more on her website.

If you are interested in purchasing her new cookbook, consider purchasing it from this local bookshop or this local bookshop or your favourite book retailer.

Allison Hepworth - August 9, 2023

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Halibut with Fermented Birch Leaf Sauce

Allison Hepworth - August 9, 2023

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