Sunday Roast Potatoes in Cast Iron

A practical route to deeply golden roast potatoes, using the steady heat of cast iron and a method designed for a South African Sunday table.

By Cookin · 24 September 2026 · 3 min read

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Golden roast potatoes with rosemary in a black cast-iron casserole at a warm Sunday lunch table

The best roast potatoes are a contrast: a craggy, well-coloured shell around a soft centre. Cast iron helps because it stores heat and recovers quickly when cool potatoes are added. The trade-off is space. A heavy casserole gives excellent contact heat only when the potatoes sit in a loose single layer rather than steaming in a crowd.

Choose floury potatoes, then cut evenly

Use a floury or all-purpose potato sold for roasting rather than a waxy salad potato. The variety available changes through the year, so ask your greengrocer or check the bag. Pieces of roughly 5cm cook at a similar rate and leave enough surface to roughen after parboiling.

Why cast iron earns its place

A broad cast-iron base transfers stored heat directly into the cut faces, encouraging colour where potato meets pan. Use the casserole without its lid: trapped steam is useful for a braise, but it works against a crisp roast. The vessel stays very hot at the table, so keep it on a proper trivet and leave an oven cloth beside it.

Make room for the edges

Parboiling starts the centre; a brief shake in the drained pot creates the rough exterior that catches hot fat. Once the potatoes reach the cast iron, give each piece contact with the base. Turn them once the underside has formed a proper crust rather than repeatedly disturbing them.

If the roast is not behaving

Pale and soft: the vessel may be crowded, the oil may not have been hot enough, or the oven may be running cool.
Dark outside but firm inside: the pieces are too large or the oven is too fierce; lower the heat slightly and allow more time.
Potatoes sticking badly: wait a little longer before turning. A properly formed crust usually releases more cleanly.
Uneven colour: rotate the casserole if your oven has a known hot side, and turn each piece onto a paler face.
Garlic or herbs scorching: add them for the final part of roasting rather than exposing them to the full high-heat cook.

Provisional recipe

Sunday Roast Potatoes in Cast Iron

Serves: 6 as a side
Prep: 25 min
Cook: 65 min
Total: 90 min
Difficulty: Easy

Ingredients

Roast potatoes

1.5kg floury or all-purpose potatoes
12g fine salt, plus extra for the cooking water
60ml neutral high-heat oil
4 garlic cloves, lightly crushed in their skins
3 rosemary sprigs
Freshly ground black pepper, to taste

To finish

Flaky salt, to taste

Method

1
Heat the oven to 220°C conventional or 200°C fan, with a rack in the upper-middle position. Peel the potatoes and cut them into even pieces of roughly 5cm.
2
Put the potatoes into a large saucepan, cover with cold water and season the water. Bring to the boil, then simmer for an indicative 8–10 minutes, until the outer edges are tender but the centres still offer resistance to a knife.
3
Drain thoroughly and leave the potatoes in the colander for 3–5 minutes so surface steam can escape. Return them to the dry saucepan, add the measured fine salt, cover and shake gently to roughen the edges without breaking the pieces apart.
4
Add the oil to a broad 4.8L cast-iron casserole and place it, uncovered, in the oven for about 8 minutes. Using dry oven gloves, set the hot vessel on a heatproof surface. Carefully add the potatoes and turn each piece in the oil, arranging them in a loose single layer with a cut face against the base.
5
Roast uncovered for 25–30 minutes without disturbing them. Turn each potato onto a paler face, add the garlic and rosemary, then roast for a further indicative 25–35 minutes. Rotate the vessel once if the oven colours unevenly.
6
The potatoes are ready when deeply golden on several sides and completely tender through the centre. Remove the rosemary stalks, season with black pepper and taste before adding flaky salt.
7
Leave the potatoes uncovered for about 5 minutes before serving. This lets excess steam escape while the cast iron keeps them warm. Serve from the casserole only on a sturdy trivet, with both handles treated as hot.

Notes

Do not use the lid while roasting; the aim is to let moisture escape.
If the potatoes cannot sit in a loose single layer, divide the batch between two suitable vessels rather than crowding them.
The stated timing remains indicative until Cookin completes its test protocol in the specified vessel and across representative ovens.
Check the care guidance for your particular cast-iron cookware before preheating it with oil.