Northern Pacific halibut is my fish of choice to have in the warmer months. It is a flat fish and deserves special care when handling. Since it can be a little more expensive, I save it for special occasions. The sauce relies on corn, which is very important to Native American culture and recipes. Use blue corn if you can get ahold of it. Otherwise, sweet corn is a great go-to.
For the sweet corn sauce: In a medium heavy-bottomed saucepan, add the canola oil, onions, garlic, thyme, bay leaf, salt and pepper. Sweat on medium heat, stirring occasionally, until the onions are softened, 7 to 10 minutes. Add the wine, if using, and cook until it evaporates, about 5 minutes.
Add the corn kernels, reserved cobs and stock. Bring to a boil over medium-high heat, then reduce the heat to medium and cook for about 10 minutes.
For the halibut: Meanwhile, in a large plastic bag, combine 5 teaspoons of the canola oil, the cumin, lemon zest and juice, salt and pepper with the halibut fillets and allow to marinate in the refrigerator for 30 minutes.
Discard the corn cobs, thyme and bay leaf from the sauce. Carefully pour the mixture into a blender and puree on high speed for 4 to 5 minutes. The natural starches will activate and thicken the sauce. Pour the sauce through a fine-mesh sieve into a clean saucepan. Simmer over low heat until it reduces by half, about 15 minutes.
To finish the halibut, in a medium sauté pan, heat the butter and remaining 3 teaspoons canola oil over high heat until the butter melts and the oil is hot (a little smoke indicates it’s ready). Place the halibut fillets in the pan skin-side up and cook until a nice crust forms on the bottoms, about 4 minutes. Carefully flip the fillets and cook 3 minutes more. Lower the heat and continue to cook until the internal temperature registers 140 degrees F, about 4 minutes. Let rest, covered with foil, for a few minutes. Serve topped with the sweet corn sauce.
When blending hot liquid, first let it cool for five minutes or so, then transfer it to a blender, filling only halfway. Put the lid on, leaving one corner open. Cover the lid with a kitchen towel to catch splatters, and pulse until smooth.