Roasted Sweet Potatoes

Ingredients

• 2 tablespoons, plus more to tasteKosher salt
• 1/2 teaspoonBicarbonate of soda
• 1.8 kg (4 pounds)Orange sweet potatoes, peeled and cut into large chunks about 6–7.5 cm (2 1/2–3 inches)
• 75 ml (5 tablespoons)Extra-virgin olive oil
• 1 tablespoonFresh rosemary, chopped (or thyme)
• 3 clovesGarlic, minced
• To tasteFreshly ground black pepper
• 1 tablespoonFresh parsley, minced

Instructions

1. 1

   Heat the oven

   Set a rack in the centre of the oven and preheat it to 230°C (450°F).

2. 2

   Boil the water

   Bring 1.9 litres (2 quarts) of water and 2 tablespoons of kosher salt to the boil in a large pot over high heat.

3. 3

   Add the potatoes

   Stir in the bicarbonate of soda, then carefully add the sweet potato chunks and stir gently.

4. 4

   Parboil the chunks

   Bring the water back to the boil, then lower it to a simmer. Cook for about 10 minutes after it returns to the boil, until a knife enters a chunk slowly without it feeling hard or falling apart.

5. 5

   Infuse the oil

   Meanwhile, put the olive oil, rosemary, garlic and a few pinches of black pepper in a small saucepan over a medium heat. Cook for about 3 minutes, stirring the pan constantly, until the garlic just starts to turn more yellow.

6. 6

   Strain the oil

   Quickly strain the oil through a fine-mesh sieve into a large bowl. Set the strained garlic and rosemary aside separately.

7. 7

   Dry the potatoes

   When the potatoes are ready, carefully drain them into the sink. Leave them in the hot pot for about 30 seconds so excess moisture can evaporate.

8. 8

   Coat the chunks

   Transfer the potatoes to the bowl of infused oil and season with a little more salt and pepper to taste. Shake and toss vigorously until a thick, mashed-potato-like coating forms on the chunks. Arrange them apart on a large, rimmed baking tray lined with baking parchment.

9. 9

   Roast the potatoes

   Roast for 20 minutes. Use a thin, flexible metal spatula to release any stuck pieces, then shake the tray and turn the potatoes.

10. 10

    Finish roasting

    Roast for a further 25–35 minutes, turning and shaking the tray a few times, until the potatoes are crisp all over and deep golden brown.

11. 11

    Add the herbs

    Transfer the potatoes to a large bowl. Add the reserved garlic and rosemary mixture and the minced parsley, then toss to coat. Season with more salt and pepper to taste.

12. 12

    Serve straight away

    Serve the roasted sweet potatoes immediately.

What are roasted sweet potatoes?

Roasted sweet potatoes are a straightforward side dish made by cooking sweet potato pieces until their edges brown and their centres soften. Sweet potatoes are used in many cuisines around the world, and this method focuses on a crisp, well-seasoned finish.

Parboiling and roughing up the chunks before roasting gives the surface a starchy coating. Rosemary, garlic and parsley bring an aromatic, savoury contrast to the potatoes' natural sweetness.

Nutrition and macros by portion

The nutrition label shows one serving as written: 275 calories, 4g protein, 46g carbs, 9g fat.

The sweet potatoes provide most of the carbohydrates, while the olive oil contributes most of the fat. The potatoes provide a little protein, but this side is not a major protein source; serve it with a protein-rich main and vegetables for a more balanced plate.

Why parboil with bicarbonate of soda?

Bicarbonate of soda makes the cooking water alkaline, helping soften the potato surfaces so they break down slightly when tossed. That roughened coating can crisp up in the oven.

Cook until a knife can enter a chunk without resistance, but stop before the pieces collapse. Drain carefully and let them steam-dry briefly in the hot pot.

Infuse the oil gently

Garlic and rosemary flavour the olive oil before it coats the potatoes. Keep the pan over a medium heat and stir constantly so the garlic turns just slightly more yellow rather than browning too far.

Straining separates the flavoured oil from the herbs and garlic. Keep the solids to add at the end, where they can lend flavour without spending the full roasting time in the oven.

Build the crisp coating

Toss the drained chunks vigorously with the infused oil until their surfaces look rough and coated with a thick, paste-like layer. This step is meant to scuff the potatoes, not keep them pristine.

Spread them out on the lined tray with space between pieces. Crowded chunks are more likely to soften in their own steam than brown evenly.

Watch the colour and texture

After the first 20 minutes, loosen any pieces stuck to the tray and turn them. Continue roasting for 25–35 minutes, shaking and turning the chunks a few times.

Look for a deep golden-brown surface and crisp edges all around. The exact finishing time depends on the size of the chunks and how your oven cooks.

What to serve alongside

These potatoes work as a side for roasted vegetables, a savoury pie, or a main course with a source of protein. Their sweet, herby flavour also pairs well with greens or a sharp, tangy salad.

Serve them as soon as they are tossed with the garlic, rosemary and parsley, while their crisp surfaces are at their best.

Recipe notes & tips

• Cut the sweet potatoes into chunks of roughly similar size so they cook at a similar pace.
• Use a large pot so the chunks can be added and stirred without crowding.
• Let the potatoes rest in the hot pot for about 30 seconds after draining to release excess moisture.
• Keep the sweet potato pieces separate on the baking tray to help them brown.
• Use a thin, flexible spatula to loosen any pieces that stick before turning them.
• Add the reserved garlic and rosemary mixture and parsley after roasting.

Variations

• Try thyme: use fresh chopped thyme in place of the rosemary.
• Add a little chilli: toss in a pinch of chilli flakes with the oil for gentle heat.
• Use smoked paprika: add a small amount to the oil for a smoky note.
• Finish with lemon: squeeze a little lemon juice over the potatoes just before serving.
• Change the herbs: replace the parsley garnish with another fresh herb you enjoy.

Common mistakes to avoid

• Overcooking during parboiling: stop when a knife enters without resistance but the chunks still hold their shape.
• Skipping the steam-dry: leave the drained potatoes in the hot pot for about 30 seconds so excess moisture can escape.
• Tossing too gently: shake and toss vigorously enough to roughen the surfaces and build the coating.
• Crowding the tray: space out the chunks so their edges can roast rather than steam.
• Letting the garlic brown: stir the infused oil constantly and remove it once the garlic starts turning more yellow.
• Turning too late: loosen and turn the potatoes after the first 20 minutes, then check and turn them a few more times.

How to store

Keep leftovers in an airtight container in the fridge for up to 3 days. Reheat on a baking tray in a hot oven until warmed through and crisped again; the microwave will soften the exterior.

Frequently asked questions