Recipe

Delicate Baked Flounder

Tender, flaky flounder baked fast with lemon, garlic, and herb butter. Light enough for weeknights, fancy enough to pretend you planned it.

By Matt Campbell

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4.8

Freshly baked flounder fillets on a rimmed baking sheet with lemon slices and chopped parsley, shot on a bright kitchen counter

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Flounder is the kind of fish that does not want a lot of drama. It is delicate, mild, and cooks so quickly that if you walk away to answer one text, it will start drafting its resignation letter. The good news: when you treat it gently, you get a dinner that tastes restaurant-ish with weeknight effort.

This delicate baked flounder is my go-to for the nights when I want something bright and buttery, but I do not want to babysit a pan of fish. We bake it just until it flakes, spoon over lemon herb butter, and call it a personal victory.

A hand squeezing a lemon wedge over baked flounder fillets on a rimmed baking sheet, with visible steam rising

Why It Works

Fast cook time: Flounder fillets are thin, so the oven does the work in about 10 minutes.
Moist and tender: A quick lemon herb butter keeps the fish from drying out and adds flavor without burying it.
Bright, not bland: Lemon zest plus a little garlic wakes up the mild fish in the best way.
Low mess: One baking sheet, one small bowl, and you are basically done.

What to serve with it: roasted asparagus, garlicky green beans, rice pilaf, couscous, smashed potatoes, or a big crunchy salad with something tangy in the dressing.

Storage Tips

How to Store

Refrigerate: Cool leftovers, then store in an airtight container for 1 to 2 days for best quality (up to 3 days is generally fine, but it will taste less fresh).
Reheat gently: Warm in a 275°F oven, covered, just until heated through. Time will vary, but start checking around 8 minutes. If you like numbers, aim for 125 to 130°F for “just warmed” so it does not overcook.
Leftover ideas: Flake it into a salad, fold into scrambled eggs, or make a quick fish taco situation with cabbage and a squeeze of lime.
Freezing: Not my favorite for cooked flounder because it is so delicate, but you can freeze it for 1 to 2 months for best quality. It can be frozen longer, but texture tends to suffer. Thaw overnight in the fridge and reheat gently.

Common Questions

How do I know when flounder is done?

When it turns opaque and flakes easily with a fork. The edges may start to separate into flakes first, and the center should look opaque and feel just barely firm. If it is dry and shredding like paper, it went a bit too long.

What temperature should baked flounder be?

For food safety, fish is commonly considered done at 145°F in the thickest part. With very thin fillets, it can be tricky to measure, so use flaking and opacity as your main cues.

Can I use frozen flounder?

Yes, just thaw it first. Pat it very dry before baking so it roasts gently instead of steaming in its own puddle.

Can I swap in another fish?

Absolutely. Sole or tilapia work well with the same timing. Thicker fish like haddock or cod will need a few extra minutes.

Why is my flounder watery?

Usually it is excess moisture from the fish (especially if previously frozen) or the pan is crowded. Thaw fully, pat dry, and use a large rimmed baking sheet so the fillets can lie in a single layer without overlapping.

How long do I bake it if my fillets are thicker?

Flounder is usually thin, but thickness varies. Plan on 8 to 12 minutes for typical thin fillets. If yours are thicker, start checking at 10 minutes and keep going until opaque and flaky. When in doubt, pull it early and let carryover heat finish the job.

Matt Campbell

I have always had a huge passion for the culinary arts, people, working as a team, and so on. I wanted to pursue my love for cooking initially at Virginia Commonwealth University with a culinary arts degree; however, I instead decided to apply myself and acquire more practical skills. My end goal is to eventually open my own restaurant or similar establishment.

Kitchen Essentials

Large rimmed baking sheet (best for 1 1/2 lb of flounder in a single layer)
Parchment paper or foil (optional, for easy cleanup)
Small bowl for mixing the butter
Microplane or fine grater (for lemon zest)
Measuring spoons
Fish spatula or wide spatula (helpful for serving)
Instant-read thermometer (optional but handy)

I started baking flounder on nights when I wanted something that felt a little fancy, but my energy level was more “sit on the kitchen floor and eat pickles” than “sear and baste.” Flounder saved me. It is quick, forgiving if you set a timer, and it loves a simple butter situation.

Now it is one of my favorite fridge-cleanout dinners because it plays nice with whatever I have: parsley or dill, lemon or lime, even that one sad shallot rolling around in the crisper. And yes, I have absolutely turned leftovers into a midnight fish salad that looked suspiciously impressive in the glow of the fridge light.