How to Make It
Season fish with salt and let stand 20 minutes. Pat dry with a paper towel.
Grease a baking sheet, or line it with aluminum foil and spray with cooking spray. Place fish on sheet, folding the last 1 inch to 2 inches of the fillet under itself to make the fillet an even thickness.
Preheat broiler to high. Combine yogurt, mayonnaise, sherry, and herbs, and stir until fully incorporated.
Place fish under the broiler on the highest rack as close to the heat source as possible, ensuring fillets are spread evenly under the heating unit. Broil, rotating if necessary to brown evenly, until browned, 4 to 5 minutes. Remove from oven; spoon sauce over fillets, and spread as thick as possible. Return fish to oven for about 2 minutes. Fish is fully cooked when it flakes easily.