Classic Oven-Baked Jacket Potatoes

Set the oven to 220°C conventional / 200°C fan / gas 7. Put a clean wire shelf in the middle and a shallow baking tray on the shelf below to catch drips. Allow about 15 minutes for preheating, or until the oven indicates it is ready. Prepare the potatoes during this window as described next; do not start baking before the oven is hot. A slower oven extends the elapsed time.

Allow about 8 minutes within the preheating window for all preparation. Check and weigh the four floury baking potatoes: each should weigh 250–300g, with a combined weight of 1–1.2kg. Scrub under running water, then dry thoroughly with kitchen paper, including any creases. Leave the skins on. Prick each potato in several places with a fork. Measure the olive oil into a small bowl and rub all 10ml in a thin coating over the four potatoes; sprinkle all 2g fine salt evenly over their skins. Keep them whole, with no foil wrapping. If preparation runs beyond preheating, wait until both are complete and add the extra elapsed time.

Using oven gloves to handle the shelf if necessary, arrange the potatoes directly on the middle wire shelf with at least 3cm between them and away from the oven walls. Bake uncovered for 20 minutes at 220°C conventional / 200°C fan / gas 7, starting the timer once the potatoes are loaded. The skins should begin to dry and colour; this is not yet a tenderness test.

Without wrapping the potatoes, reduce the oven setting to 190°C conventional / 170°C fan / gas 5 and bake for a further 60 minutes. This stage includes the oven's gradual temperature drop; do not cool the oven separately. At the end, use oven gloves and a folded clean tea towel to steady each potato on a plate and slide a small knife into its centre. The knife should pass through with little resistance, the flesh should yield when gently pressed, and the skin should feel dry and crisp. Checking is included in this stage's allowance. If any centre is firm, return that potato to the wire shelf and bake at the lower setting in further 5-minute cycles, checking after each cycle. Allow roughly 60–80 minutes for this lower-heat stage, but follow tenderness rather than a deadline: every extra cycle adds 5 minutes and particularly slow ovens or awkward shapes can take longer still. Check each potato individually and remove those that are ready.

As each potato becomes tender, transfer it to a serving plate with oven gloves. Allow about 3 minutes in total to open and finish all four: steady each with a folded tea towel, cut a cross into the top and gently press the sides to open it, keeping hands and face clear of escaping steam. Fluff the exposed flesh with a fork without scraping away the crisp skin. Serve promptly, uncovered, with any separately prepared accompaniments. Do not add an intentional covered rest, which would trap steam and soften the skin. If the potatoes finish at different times, split each promptly rather than holding it wrapped while the others cook; the recipe does not promise simultaneous completion. There is no butter, cheese or other topping in this base recipe.