Squidgy in the middle and crisp on the outside, these fries are baked in the oven with a piquant coating of ground cumin, smoked paprika and cayenne chilli.
Not all potatoes are created equally. Recipes often specify whether to use a waxy variety of potato (Charlotte, Jersey Royal, new potatoes), or a floury variety (Desiree, Estima, King Edward, Maris Piper). Waxy varieties are higher in starch and lower in moisture. This gives them a firmer texture, and makes them suited to dishes where the potato needs to hold together or crisp up. Waxy potatoes are good for fries, potato salads, and Spanish tortillas. Floury varieties are lower in starch and higher in moisture. This means that they break down when cooked, resulting in a light and creamy texture with rough, broken edges. Floury potatoes are good for mashed potato, baked potatoes, and roast potatoes.
Sweet potatoes are lower in starch and higher in moisture, which means they can be difficult to crisp up. Left to its own devices, a baked sweet potato wants to be soft and relaxed, and does not want to perform a ramrod stiff salute. You can coax sweet potatoes into more fry-like behaviour by removing as much moisture as possible during the cooking process. This involves starting with bone dry potatoes, and militantly spacing the fries out on the tray so that the steam can escape and evaporate in the oven.
Tips & Tricks
- Dry potatoes well – preferably, wash your potatoes earlier in the day so they have time to dry completely. Otherwise the cooking oil will not stick to the surface
- Preheat the tray – the hot metal will crisp up the underside
- Grease the tray – this stops the fries from sticking to the tray and breaking apart when you need to turn them
- Do not over-crowd the tray – if the fries are arranged in more than one layer, or placed closely together, they will steam rather than roast and brown
- Add salt after cooking – if you add salt before cooking, this draws out moisture in the oven, adding more steam
- Leave to stand – this allows more steam to escape, giving the fries a firmer texture when you move them
- 2 medium sweet potatoes (600g)
- 1 tablespoon cooking oil (I used olive oil)
- 1 teaspoon smoked paprika
- 1/2 teaspoon ground cumin
- a pinch of cayenne chilli pepper (depending on preferred spiciness)
- 1/2 teaspoon salt
for greasing the roasting tray:
- 1 teaspoon cooking oil (I used olive oil)
- Preheat the oven to 220°C/425°F. Place a large metal roasting tray in the oven to warm up.
- Chop the sweet potato into equally-sized pieces that will cook evenly. Place in a large bowl. Add the cooking oil, smoked paprika, cumin and cayenne. Use your hands to toss until the fries are evenly coated in oil and seasoning.
- Remove the preheated tray from the oven and brush with a teaspoon of cooking oil. This will stop the fries from sticking to the tray.
- Arrange the fries in a single layer on the roasting tray, giving them plenty of room to roast and caramelise – use two trays if necessary.
- Transfer to the highest shelf of the preheated oven and cook for 15 minutes. Remove from the oven and flip the fries. Return to the oven, turning the tray for even colouring. Cook for another 10 minutes, or until browned.
- Remove from the oven, and sprinkle over the salt. Leave to cool on the tray for 5 minutes before transferring to a serving dish. Serve with a dollop of cool mayonnaise.