Cast iron dishes that can be used for a tarte tatin or the perfect roast potatoes

An Outdoor Cook's Notebook - Entry 2 - August 2026

Same pan, savoury one night, sweet the next

Same pan, savoury one night, sweet the next. That's not a compromise - that's rather the point of owning a good one. A cast iron skillet or shallow Dutch oven that goes from grill grate to hood to table earns its keep in a way that most single-purpose kit simply doesn't. Roast potatoes and a tarte tatin ask almost identical things of their pan: high, sustained heat held evenly, and a surface that releases food cleanly when it's time to turn it out. A thin baking tray can't hold that heat. A nonstick pan won't take the temperatures involved without protest. Cast iron does both without complaint, and has been doing so for long enough that there's not much left to prove.

The science bit

Cast iron is not especially quick at conducting heat - copper and aluminium move heat faster. What cast iron does instead is store it. The metal is dense, and cast iron pans are typically thicker than pans of similar size made from other materials. Those two facts together mean that once a cast iron dish is properly hot, it holds a genuinely large amount of thermal energy - more than copper, aluminium, or stainless steel at the same temperature. Drop cold, wet, par-boiled potatoes into a well-preheated cast iron dish and the pan barely registers the intrusion. The heat already stored in the iron keeps being applied. A thin tray, by contrast, loses temperature fast the moment cold food lands on it, and never quite recovers.

That stored heat is what drives off moisture and develops real colour on the base of a potato, or sets a caramel crust properly. The food needs the surface to stay hot enough, long enough. Cast iron won't let that heat drop away the way a lighter pan will.

The trade-off is worth knowing clearly. That same thermal mass makes cast iron slow to heat up. Expect a solid ten minutes of proper preheating before the entire base of the dish is evenly hot and doing its job fully. Rushing that stage is the single most common reason results disappoint.

The seasoning layer that makes cast iron release food cleanly - essential for turning out a tarte tatin without half of it staying in the pan - is itself a piece of surface science. As Meathead's AmazingRibs.com explains it, metal surfaces, no matter how smooth they look to the naked eye, have "tiny imperfections, irregularities, and uneven surfaces." Repeated thin layers of oil, baked on at high temperature, polymerise into a smooth, slightly slick coating that fills those microscopic pits. That's the layer a tarte tatin relies on when it gets flipped.

Practical use

For roast potatoes, the method that actually uses the thermal mass properly is to preheat the empty dish thoroughly first. The Kamado Joe masterclass recipe for crispy roasted duck fat potatoes puts the target at 230°C before the fat and potatoes go in - the pan needs to be hot before anything else happens, because, as they put it, "this helps to make them crispy." Par-boil the potatoes first, dry them well, then add them to genuinely hot fat in a genuinely hot pan. Twenty-five to thirty minutes at that temperature gives the base time to colour properly rather than steam. For something like Pommes Anna - layered potato and butter, gentle and slow rather than blasted - indirect heat around 190°C works well, letting the cast iron's steady warmth do the work of a careful, even crisp.

For a tarte tatin, the caramel stage is where precision pays. Sugar develops real caramel flavour once it's properly cooked through; a reliable target is around 166°C, though colour and smell are as useful as the number itself. Pull it a shade paler than you think you want. The caramelisation process is exothermic - it gives off its own heat - so the temperature can keep climbing briefly after the pan comes off direct heat, and it's easy to overshoot without noticing until the colour's already gone too dark. Once the fruit and caramel are settled in the dish and the pastry lid is on, most approaches run the tart at 200-220°C until the pastry has coloured and set, sometimes dropping the temperature slightly to finish the fruit through underneath.

Care and common mistakes

Do:

• Preheat the empty dish for a full ten minutes before fat or food goes in.
• Dry the pan promptly and thoroughly after washing - damp cast iron rusts quickly.
• Let the dish cool a little before it meets cold water.
• Pull the caramel a shade paler than you think is right, and account for the residual heat it generates itself.
• Make sure the pan is clean and properly dry between a savoury and a sweet use, so flavours don't carry over.

Don't:

• Add potatoes to a cold or barely warm pan - they'll steam rather than sear, and no amount of extra time in the oven will rescue the crust.
• Overcrowd the dish - too many potatoes trap their own moisture and the result is the same.
• Plunge a hot cast iron dish into cold water - repeated thermal shock weakens the metal over time.
• Take the caramel too far or cook it too dry; pushed past its point it turns bitter, and without enough moisture from the fruit it sets hard and toffee-like rather than staying supple.

Compatibility across cooking formats

This genuinely works across formats, which is part of the appeal. On gas, a cast iron dish sits directly on the grates as an outdoor hob, or goes under the hood as an oven substitute. The Napoleon Cast Iron Dutch Oven is built with exactly that flexibility in mind - suitable for use on or in the oven, the barbecue, and side burners, over or directly in charcoal, and even in a fire pit - and the lid doubles as a skillet in its own right, which suits a roast potato session as easily as a tarte tatin base.

On a kamado, the precise, steady temperature control suits both dishes well. Whether that's a hot 230°C sear for potatoes or a gentler 190°C indirect bake, a kamado holds those temperatures reliably in a way that makes cast iron's slow-and-steady approach feel entirely at home.

A wood-fired oven is the one to be more careful with. The ambient heat runs far hotter and less controllable than a domestic oven or a kamado - excellent for finishing potatoes fast in residual heat once the main fire's died back, but risky for a tarte tatin's caramel, which wants a steadier, lower, more controllable heat than a blazing wood oven typically offers. Save the wood oven for the potatoes. Keep the tarte tatin to gas, kamado, or a conventional indoor oven.

Questions people actually ask

Why do my roast potatoes go soggy?

The soggy potato question comes up regularly. Almost always it's a pan that wasn't properly preheated before the fat and potatoes went in, or a dish that was overcrowded. Either way the result is the same: the potatoes steam in their own moisture rather than sear, and no amount of extra time in the oven will produce a proper crust once that's happened. The fix is always the same - hot pan, dry potatoes, enough space between them.

Can I move cast iron between a kamado and a conventional oven?

Whether cast iron is safe to move between a kamado and a conventional oven is a reasonable thing to wonder. It is - that versatility is one of cast iron's genuine strengths. The important thing is handling it with proper gloves throughout. Cast iron holds serious heat for a long time after leaving direct fire, longer than most people expect, and it gives no visible warning that it's still dangerous to touch.

Why does my tarte tatin caramel set hard?

On the tarte tatin side, the caramel going hard and toffee-like as it cools usually means it was taken a touch too far, or cooked too dry without enough moisture from the fruit to keep it supple once it sets. The exothermic nature of caramelisation - the way it keeps generating its own heat for a moment after the pan comes off the fire - means it's genuinely easy to overshoot, especially the first few times. Pulling it earlier than feels right, and trusting the residual heat to carry it the last fraction, is the habit worth building.

See it cooked at Cedar Nursery

Cast iron cookery is one of those things that makes considerably more sense once you've watched it happen in front of you. Visit us at Kitchen in the Garden at Cedar Nursery in Cobham, Surrey, and see these techniques demonstrated on the outdoor cooking setups we stock and use ourselves. Whether you're looking for the right pan, the right grill, or simply a clearer picture of how outdoor cooking actually works in practice, our team is here to help.

Featured image: Photo by Klaus Nielsen on Pexels

Come and see one cooked on. Kitchen in the Garden, Cobham, Surrey.