Mackerel fillets are brushed with English mustard and butter, then baked with lemon. The sharp mustard and citrus balance the fish's richness. Prepare the sides before the fish goes into the oven, and check the thickest part is cooked before serving.
Before you start
A short ingredient list and one oven dish keep preparation straightforward. Serve with new potatoes and a dressed salad.
What you'll need
Gather everything first, then the cooking feels calmer.
Cook along
Take it step by step; seafood rewards a calm hand.
- 1
Heat the oven to 200C/180C fan/gas 6 and lightly oil a baking tray or shallow dish.
- 2
Pat the mackerel fillets dry with kitchen paper and lay them skin-side down on the tray.
- 3
Mix the softened butter with the English mustard and the juice of half the lemon, then season with a little salt and pepper.
- 4
Spread the mustard butter evenly over the flesh side of each fillet.
- 5
Drizzle over the olive oil and bake for 12 to 15 minutes, until the flesh is opaque and flakes easily with a fork.
- 6
Serve straight away with the lemon wedges for squeezing over.
This works just as nicely on the BBQ, skin-side down over medium coals until the flesh turns opaque. The same mustard butter is lovely on other oily fish, so if you've come home with sardines or herring instead, use those and simply shorten the cooking time for smaller fish. English mustard gives a proper kick, but a milder wholegrain or Dijon is just as good if that's what you have in. We like it with new potatoes and something sharp alongside, like a dressed leaf salad to cut through the richness. If you've a real glut of mackerel, it's also the classic fish for smoking your own at home.
Serve it with
Serve straight from the oven with lemon wedges for squeezing over. New potatoes and a sharp dressed leaf salad cut nicely through the richness.
Common questions
- How long does mackerel take to bake?
- Mackerel fillets need about 12 to 15 minutes at 200C/180C fan/gas 6. They're done when the flesh has turned from translucent to opaque and flakes easily when you press it with a fork.
- Can I cook this on the barbecue instead?
- Absolutely, mackerel loves the BBQ. Lay the mustard-buttered fillets skin-side down over medium coals and cook until the flesh is opaque, usually around 5 to 6 minutes. The skin crisps up beautifully.
- What other fish can I use?
- Any oily fish takes well to this. Sardines and herring are both excellent, though smaller fish will cook a little quicker, so keep an eye on them.
- Do I have to use English mustard?
- English mustard gives the sharpest, most warming kick, but Dijon or a grainy wholegrain mustard both work well if that's what's in the cupboard.
- What should I serve with baked mackerel?
- Something fresh and a little sharp balances the richness, think new potatoes, a horseradish or mustard potato salad, dressed leaves, or wilted greens with a squeeze of lemon.
- Is mackerel a sustainable choice?
- Line-caught Cornish mackerel is one of the more sustainable fish you can buy. Have a word with your fishmonger about where and how it was caught.
