I would have thought a fishermonger should be able to get it. It's a lovely, light sweet meat.
Here's an American recipe and I love the lemon combination with halibut:
With this halibut recipe, the fish and asparagus cook together on the same sheet pan, just add a side dish like couscous or wild rice to round out your dinner. Roasting at a low temperature yields flaky, tender fish; it's also a great way to prepare asparagus. Japanese Panko breadcrumbs are bigger and flakier than regular breadcrumbs and will yield a crisp result similar to tempura (but if you are stuck go with normal ones, the coarser the better). Look for them in the Asian foods aisle at well-stocked supermarkets. Use a rimmed sheet pan so that the lemon butter and juices won't drip off the pan, line the pan with parchment paper for easy clean-up.
Prep Time: 10 minutes
Cook Time: 25 minutes
Total Time: 35 minutes
Yield: 4 servings
Ingredients:
4 oz panko crumbs
2 teaspoons grated lemon peel
4 halibut fillets, 6 ounces each
Salt and pepper
1 pound asparagus, ends trimmed
4 oz butter, melted
2 tablespoons lemon juice
1 tablespoon capers
Preparation:
Preheat oven to 300˚F. In a small bowl, combine the panko breadcrumbs and the lemon peel. Season the halibut on both sides with salt and pepper and place it on a parchment-lined rimmed sheet pan.
Press the breadcrumb mixture onto the top of the halibut, using about 2 tablespoons per fillet.
Arrange the asparagus in a single layer on the pan around the halibut fillets. In a small bowl, combine the butter, lemon juice and capers, and drizzle the mixture evenly over the halibut and the asparagus.
Roast at 300˚F for 20 to 25 minutes, until the fish is opaque all the way through and it flakes easily. If desired, put the sheet pan under the broiler (grill) for 1 to 2 minutes to brown the breadcrumbs.
To serve, divide the asparagus onto 4 plates, arranging stalks in a row, and place fish on top of the asparagus. Use a spoon to scoop up capers from the pan and scatter them over the fish and asparagus on each plate.