Lemon Baked Fish

About as straightforward as fish gets. Flounder or haddock fillets laid in a single layer, topped with a quick sauce of melted butter, fresh lemon juice, grated lemon zest, and a whisper of rosemary, then baked until the flesh flakes apart at the touch of a fork.

Using both lemon juice and zest is what gives this its bright citrus punch. The juice provides acidity that cuts through the richness of the butter, while the zest carries the concentrated lemon oils that perfume the fish as it bakes. Together they do more than either could alone.

A single layer in the baking pan is important. Stacking or overlapping fillets means uneven cooking, with some pieces overdone and others still raw in the middle. Give each fillet its own space so the heat circulates evenly.

Kitchen Tips

• Test for doneness early. Thin fillets like flounder can go from flaky to dry in just a couple of minutes past their window.
• If using frozen fillets, thaw them completely and pat dry with paper towels. Excess moisture steams the fish instead of baking it.
• Rosemary is potent, so a little goes a long way. Too much will overpower the delicate fish.

Variations

• Swap rosemary for fresh dill or thyme for a different herb profile.
• Use tilapia, sole, or cod in place of flounder or haddock.
• Add thin lemon slices on top of the fillets before baking for a prettier presentation and extra citrus flavor.