- 1 teaspoon fennel seeds, toasted
- 2 cups plain yogurt
- 1 clove garlic, minced
- 1 teaspoon minced peeled fresh ginger
- 1/2 teaspoon ground cumin
- 1/2 teaspoon ground coriander
- 1/4 teaspoon black pepper
- 1/4 teaspoon turmeric
- 1/8 teaspoon cayenne, or to taste
- 1 teaspoon salt
- 1 (6 ounce) (1-inch-thick) pieces skinless sturgeon fillet or halibut fillet with skin
- 3 tablespoons finely chopped fresh mint
- 1/2 teaspoon finely grated fresh lemon zest
- Finely grind fennel seeds in grinder. Whisk together fennel and 1 cup yogurt with garlic, ginger, cumin, coriander, black pepper, turmeric, cayenne, and 1/2 teaspoon salt. Coat fish with yogurt mixture and marinate in a shallow baking dish, covered and chilled, 1 hour.
- While fish is marinating, whisk together remaining cup yogurt, mint, zest, and remaining 1/2 teaspoon salt to make sauce.
- Prepare grill for cooking. If using a charcoal grill, open vents on bottom of grill, then light charcoal. Charcoal is medium-hot when you can hold your hand 5 inches above rack for 3 to 4 seconds. If using a gas grill, preheat burners on high, covered, 10 minutes, then reduce heat to moderate.
- Lift fish out of marinade, letting excess drip off (discard marinade), and grill fish, covered only if using a gas grill, on lightly oiled grill rack, turning over once, until just cooked through, about 12 minutes total. (If using halibut, grill skin sides down first and grill, turning once, 8 to 9 minutes total.) Serve fish with sauce.