Baked Mackerel With Potatoes And Onions

Ingredients

• 950 g (3 medium)mackerel
• 650 g (23 oz)potatoes, peeled and sliced ½ cm thick
• 150 g (5.3 oz)red onion, thinly sliced
• 5–6garlic cloves, sliced
• ½lemon, cut into 6 thin slices
• 1 tablespoon, plus extra to servelemon juice
• 1½ tablespoons, plus extra to servedried Greek oregano
• 7 tablespoonsextra-virgin olive oil
• 60 ml (¼ cup)water
• to tastesalt
• to tasteblack pepper

Instructions

1. 1

   Prepare the mackerel

   Open the belly of each fish and remove the innards. Rinse the fish well.

2. 2

   Heat the oven

   Preheat the oven to 200°C (392°F).

3. 3

   Layer the potatoes

   Arrange the potatoes in a 28 × 18 cm (11 × 7-inch) baking dish. Scatter over the onion and half the garlic. Season with salt, pepper and ½ tablespoon of the dried oregano, then drizzle the lemon juice over the top.

4. 4

   Stuff the fish

   Put 2 lemon slices and a few slices of garlic inside the belly of each fish.

5. 5

   Arrange the fish

   Set the fish on top of the potatoes. Drizzle over the olive oil and sprinkle on the remaining oregano.

6. 6

   Add the water

   Pour 60 ml (¼ cup) water into the dish from the side, taking care not to rinse the potatoes or fish.

7. 7

   Bake covered

   Cover the baking dish with aluminium foil and bake for about 50 minutes.

8. 8

   Prepare to grill

   Remove the dish from the oven and switch the oven to its grill setting. Take off the foil and place the dish on the top oven rack.

9. 9

   Brown the top

   Grill the fish for 7–10 minutes, or until the top looks nicely roasted.

10. 10

    Rest and serve

    Leave the dish to stand for 10–15 minutes; cover it again with foil if you like. Serve with an extra squeeze of fresh lemon juice and a little more dried Greek oregano, if desired.

What is baked mackerel with potatoes?

This is a Greek-style oven dish of whole mackerel baked over potatoes and onions, seasoned with lemon, garlic and oregano. It brings together fish and its side in one pan, with the cooking juices flavouring the potatoes.

Here, the fish is covered for most of the bake, which helps keep it moist, then briefly grilled uncovered for a roasted finish.

Nutrition and macros by portion

The nutrition label shows one serving as written: 996 calories, 69g protein, 48g carbs, 58g fat.

The potatoes provide most of the carbohydrates, while mackerel contributes much of the protein and fat; the olive oil adds further fat. Pair a serving with a green salad or other vegetables for a fresh, fibre-rich balance.

Why mackerel works here

Oily fish such as mackerel has a rich flavour that stands up well to lemon, garlic and dried oregano. Leaving it whole also means the fish sits neatly over the potatoes while it cooks.

Check that the fish has been cleaned before seasoning and stuffing it. The recipe calls for rinsing it after removing the innards.

Building the potato layer

Even slices: cut the peeled potatoes about ½ cm thick so they cook at a similar pace. Arrange them in the specified 28 × 18 cm baking dish rather than piling them into a deep mound.

Aromatics: the onion and half the garlic go over the potatoes, while the remaining garlic is tucked into the fish. Lemon juice seasons the base; the lemon slices add fragrance inside the fish.

Keeping the fish moist

Covered bake: foil traps steam while the fish and potatoes cook for about 50 minutes at 200°C. Pour the water in from the side so it reaches the dish without washing the seasoning off the ingredients.

Grilled finish: uncover the dish and use the top rack for the final 7–10 minutes. Keep an eye on it, as the surface can brown quickly under the grill.

How to tell it is ready

The top should look roasted after the short grilling stage. The recipe also gives the potatoes time to soften during the covered bake; if checking, they should be tender when pierced.

Let the dish rest for 10–15 minutes before serving. This gives the hot juices time to settle and makes it easier to portion the fish and potatoes.

Serving the dish

Serve the fish with the potatoes and onions from the baking dish, spooning over some of the cooking juices. Finish with extra lemon juice and dried Greek oregano if you like.

A crisp green salad or simply dressed vegetables make a fresh contrast to the rich fish and olive oil. Keep any extra sides straightforward so the baked dish remains the focus.

Recipe notes & tips

• Slice the potatoes evenly so they soften at roughly the same rate.
• Keep the lemon juice and added water away from the top of the fish when pouring them into the dish.
• Use the top rack only for the final grilling stage, as directed.
• Watch closely during grilling and stop when the fish looks roasted on top.
• Rest the dish for 10–15 minutes before serving.
• Offer extra lemon and oregano at the table so each person can season their portion.

Variations

• Add fresh herbs: Scatter chopped parsley over the dish just before serving.
• Use yellow onion: Replace the red onion with thinly sliced yellow onion.
• Add chilli: Sprinkle a little chilli flakes over the potatoes for gentle heat.
• Use fresh oregano: Finish with fresh oregano leaves in place of extra dried oregano.
• Serve with greens: Add a simple green salad alongside the fish and potatoes.

Common mistakes to avoid

• Uneven potato slices: Cut them to a consistent ½ cm thickness so they cook evenly.
• Pouring water over the ingredients: Add it from the side of the dish to avoid rinsing away seasoning.
• Skipping the cover: Keep the dish covered for the main bake to help retain moisture.
• Grilling for too long: Check the fish during the 7–10-minute finish so the top does not over-brown.
• Serving immediately: Rest the dish for 10–15 minutes before portioning.

How to store

Refrigerate leftovers in a covered container and eat within 2 days. Reheat until piping hot in a covered ovenproof dish at a moderate temperature, or use a microwave; add a small splash of water if the potatoes seem dry.

Frequently asked questions