A thick fillet of white fish like cod or haddock, dressed appropriately for the season, is a fairly ubiquitous presentation on restaurant menus around where I live in Boston. I’m here for it: Moist, flaky fish is an ideal canvas for a buttery sauce or citrusy relish. Often described as “pan-roasted,” the menu reveals how restaurant chefs achieve perfectly-cooked, thick fish fillets: Seared first on the stovetop, then transferred to the oven to finish cooking through.
This two-step restaurant technique is also the test kitchen’s go-to method for cooking cod, haddock, black sea bass, pollock, and hake (not to mention, thick steaks and chops) at home. But for a light golden-brown, just-crispy crust to encase the silky fillet, we turn to an additional—and surprising—ingredient: sugar.