Try this Baked Fish recipe.
Scaling a seafood dish down to a single pound requires careful attention to pan sizing to prevent butter from pooling too deeply and boiling the protein rather than roasting it. Using a 9x9-inch square pan keeps the surface area constrained, ensuring the fat clings to the fillets. Butter delivers roughly 80 to 82 percent milk fat with the remainder water and milk solids, which browns slightly during baking to add depth compared to neutral oils.
Combining melted butter with lemon juice creates a traditional emulsion base that protects delicate flesh from drying out in dry heat. Acid denatures protein structures slightly on contact, but when combined with a high fat content, it slows moisture loss during the initial phase of baking. Grated onion introduces sulfur compounds that mellow significantly under direct heat, diffusing mild allium flavor directly into the dripping sauce without raw bite.
Baking at 350 degrees Fahrenheit provides a moderate thermal environment that prevents the exterior from tightening before the interior reaches safety thresholds. Pull the pan from the oven right when the thickest part of the fillet turns opaque and flakes apart under gentle pressure from a fork tined horizontally. Total oven time typically spans 25 to 30 minutes depending on fillet thickness, though checking early prevents rubbery textures.