Preheat the oven to 200°C. Use a baking tray that is large enough to fit the potatoes on half of its area. You will require the extra space later once you smash them. 

Score the potatoes along their length, on both sides, using a knife. Spread them out on the baking tray and pour in the wine and water. Sprinkle the ground coriander on top of the potatoes and in the liquid. Place them in the oven for 30min. 

Remove the tray from the oven and pour the remaining liquid in a heat proof jug/bowl. At this stage you may place the potatoes on a plate so they don’t tip over while you are pouring. Increase the oven temperature to 230°C.

Return the potatoes in the tray and use a masher or the back of a mug to push them down enough to smash and open. At this stage allow the potatoes to air dry for 10min so that they turn out a bit crispier on the outside.

Pour 3-4 tbs of the remaining liquid around the potatoes (not on top of them). Just enough to soak for the bottom part of the potato, otherwise it will be too soggy. Then drizzle the potatoes directly with the olive oil, season with salt and sprinkle the crushed coriander seeds.

Return them in the oven for a further 10-15min until they are golden brown and cooked through.