4(6- to 8-ounce) halibut steaks (3/4 to 1 inch thick)
1tablespoonvegetable oil
Whisk together olive oil, lemon juice, water, garlic, shallot, red-pepper flakes, and 1/2 tsp each of salt and pepper until salt has dissolved. Stir in parsley. Let chimichurri stand 20 minutes.
Meanwhile, prepare grill for direct-heat cooking over medium-hot charcoal (medium heat for gas). See "Grilling Procedures."
Pat fish dry, then brush with vegetable oil and sprinkle with 1/2 tsp salt and 1/4 tsp pepper (total).
Oil grill rack, then grill fish, covered only if using a gas grill, turning once, until just cooked through, 8 to 10 minutes total.
Serve fish drizzled with some of chimichurri; serve remainder on the side.
Cooks’ notes:
Halibut can be cooked in a hot oiled large (2-burner) ridged grill pan over medium heat.
Chimichurri can be made 1 hour ahead and kept, covered, at room temperature.