Slow-baked fish with lemon mustard glaze

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close-up view of slow baked fish with lemon mustard glaze on a white porcelain plate

Slow-baking fish steaks with a lemon mustard glaze is the most delicious way to cook fish. They turn out so juicy and succulent that you can’t stop yourself from eating, and eating. Spicy, tangy and tender, the slow baked fish steaks are everything that a fish dish should be. And more. Have it with some flavored rice and roasted vegetables for a weekend lunch or dinner. It’s also a perfect dish for parties that can be made in big batches for a hungry crowd.

If you are a person who wants to spend less time in the kitchen but still show off some amazing dishes that look like they’re worth a million dollars, then we are in this together. The slow baked fish with mustard dish can look like you spent hours in the kitchen, preparing and cooking ( the name contributes to half the hype) when in reality you just need 10 minutes for preparing, then leave the rest to your oven.

There’s just one thing you need to ensure: the freshness of the fish. I used mackerel here, but you can use any fish of your choice and fillets too. You just have to tweak the cooking time a bit.

Why slow baking is the best way to cook fish

  • Slow baking makes the fish juicy and tender.
  • The lemon mustard sauce melts and oozes out, making you literally drool.
  • Slow cooking preserves the nutrients of the fish since you’re not subjecting it to high temperature.

Preparing the fish steaks

Preheat oven to 100 degrees C, which is about 210 degrees F.

Mix the chili powder, salt and oil in a small bowl and coat the fish with the marinade. The lemon mustard glaze can be prepared in the meantime.

5 marinated fish steaks on a white porcelain plate

Lemon mustard glaze

Blend together Dijon mustard, garlic, chili flakes, ground cumin, salt, lemon peel, lemon juice into a smooth paste. A small blender jar is required here since the quantity of ingredients is quite less. If you don’t have one, it makes sense to make double or triple the quantity and freeze the leftover. Once you make this slow baked fish, you may get addicted to it and the frozen stuff will be used up in no time. You will thank me for this little tip. You’re welcome!

ingredients for lemon mustard glaze in a blender jar

Brush the fish steaks with lemon mustard glaze and sprinkle some cilantro on top.

5 marinated fish steaks with lemon mustard paste on a white porcelain plate ready to be baked

Slow baking

Place the fish steaks on a sheet pan or baking dish. Bake for 20 to 25 minutes. Check for doneness at the middle part of the steak. It should flake apart easily. Let it stand for 5 minutes. Devour.

I’m guilty of not letting it stand, because one of the steaks was gone before I could take a picture and I was left with only 4. I had to hurry before the other steaks vanished! Hungry people around with delicious glistening mustard glazed fish steaks on the table? That was quite an ordeal.

Fish, mustard and lemon – the combo is almost always a win-win situation.

close-up view of slow baked fish with lemon mustard glaze on a white porcelain plate

Tips to make the slow baked fish with lemon mustard sauce even better

  • Marinate the fish longer, even overnight.
  • When you blend the lemon mustard paste, add a few stalks of cilantro for added flavor.

Slow-baked fish with lemon mustard glaze

  • Servings: 4-5
  • Difficulty: easy
  • Print

Spicy juicy fish fillets slow-baked to flaky perfection with a lemon mustard glaze.


  • 5 steaks or fillets of mackerel or any fish of your choice
  • 1 teaspoon cayenne pepper or chili powder
  • 1 1/2 teaspoon salt
  • 1 tablespoon sunflower oil
  • 3 teaspoons Dijon mustard
  • 3 garlic cloves
  • 1 teaspoon chili flakes
  • 1/2 teaspoon ground cumin
  • 1 tablespoon lemon juice
  • peel of 1/2 lemon
  • a handful of fresh cilantro


  1. Prepare the marinade with cayenne pepper, oil and 1 teaspoon salt (reserve the other 1/2 teaspoon for mustard paste). Marinate the fish steaks for 10 minutes minimum.
  2. Preheat oven to 100 degrees C (about 210 degrees F).
  3. For the mustard glaze, place the rest of the ingredients except cilantro in a small blender jar and blend until smooth. (see notes)
  4. Brush fish steaks with the mustard glaze. Sprinkle cilantro on top.
  5. Place on a sheet pan and bake for 20 to 25 minutes until the fish flakes apart easily.


  • Cooking time depends on how thick the steak or fillet is. So when you’re cooking this for the first time, check if the center flakes through easily, though you might hate to poke through the juicy-looking fish. If not done, bake for 5 more minutes. With practice, you can master the timing.
  • Cilantro can be sprinkled on the fish after cooking, but you may miss out on the cooked-mustard-cilantro-flavor so good that it can be addictive.
  • Since the amount of mustard paste is quite small, you will need a small blender jar to get a smooth paste. Or you can make twice or thrice the amount and freeze the leftover. That gives you an excuse to eat more of this delicious lemon-mustard glazed fish.

More fish recipes you might want to try this week

crunchy fish patties

orange butter salmon

baked salmon kababs

pan seared salmon with mango avocado salsa

Some prawn recipes

restaurant style breaded prawns

tiger prawns baked in tomatoes and cheese


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