Mary Berry Sweet Potato Fries

These sweet potato fries are the kind of thing I throw in the oven when I don’t really feel like cooking but still want something warm and satisfying. I first made them on a Wednesday when dinner was a bit of a “what’s in the veg drawer” situation, and they completely saved the meal.

The first time, I overcrowded the tray and ended up with floppy wedges instead of crisp fries—big mistake. Once I learned the golden rule of spacing them out and flipping halfway, they turned out perfectly golden and slightly caramelised on the edges. Now they’re my go-to side for anything from burgers to a fried egg.

A FEW REASONS THIS JUST WORKS

The beauty of this recipe is in the simplicity. Three ingredients, one tray, and a hot oven—that’s it. No fancy coatings, no faff. Sweet potatoes are naturally sweet and earthy, and roasting them at high heat draws out all that flavour and gives you crispy edges with soft centres.

Most recipes load on the spices or cornstarch, but Mary keeps it minimal here—and it just works. When the technique is right, you don’t need anything else.

INGREDIENTS + WHY THEY MATTER

• Sweet potatoes (3 large / 1.5 lbs) – Go for firm ones with orange flesh. Cut evenly so they cook at the same rate.
• Olive oil (1 tbsp) – Just enough to coat—too much and they go soggy.
• Sea salt (to taste) – Sprinkled at the end to bring out the natural sweetness.

MAKING IT YOURS (WITHOUT RUINING IT)

• Spice it up? Add paprika or cumin before roasting. I’ve tried both—paprika is my favourite.
• Want garlic? Toss with garlic powder after baking (fresh burns).
• Make them smoky? A pinch of smoked salt or a touch of chipotle powder does wonders.
• Need it oil-free? You can roast them dry, but they’ll be softer and less crisp.

MISTAKES I’VE MADE (AND HOW TO AVOID THEM)

What Went Wrong	Why It Happens	How to Fix It
Fries were soft, not crisp	Overcrowded the tray	Always spread in a single layer with space
Fries burned on edges	Cut too thin or uneven	Stick to about ¼ inch thickness
Stuck to tray	Skipped parchment paper	Always line the tray or use non-stick sheet
Bland flavour	Seasoned before baking	Salt after for the best flavour boost

HOW TO MAKE MARY BERRY’S SWEET POTATO FRIES

1. Preheat the oven
   Set to 220°C (200°C fan/Gas 7) or 425°F. Line a baking sheet with parchment paper.
2. Prep the potatoes
   Peel sweet potatoes and cut into thin, even fries—about ¼ inch thick.
3. Toss with oil
   Place fries on the baking sheet. Drizzle with olive oil and toss well to coat evenly.
4. Arrange the fries
   Spread fries out in a single layer. Don’t let them touch or they’ll steam instead of crisp.
5. Bake and flip
   Roast for 20 minutes. Flip each fry, then bake another 15–20 minutes until golden and crisp.
6. Season and serve
   Sprinkle with sea salt while hot, toss gently, and serve straight away.

TIPS FROM MY KITCHEN

• I never skip the parchment—it guarantees no sticking and easy cleanup.
• I cut all the fries before starting the oven—it gives them a moment to dry out.
• I save any end bits for soup—they roast up soft and sweet but don’t fry well.

STORAGE + SERVING

• Keeps – 3 days in the fridge (sealed container).
• Freezes – Freeze in a single layer first, then bag. Keeps for 1 month.
• Reheats – Oven at 220°C for 7 mins or air fryer at 190°C for 3 mins.
• Serve with – Aioli, ketchup, or topped with feta and chilli flakes.

FREQUENTLY ASKED QUESTIONS

Q: Can I leave the skin on?
A: Absolutely—I do it all the time. Just scrub well before cutting.

Q: Can I air-fry these instead?
A: Yes! Cook at 190°C for 10–12 minutes, shaking halfway.

Q: Do I need to soak the fries first?
A: Not for this recipe. Soaking can help crispness, but it’s not necessary here.

Q: Can I cut them thicker?
A: You can, but they’ll take longer and won’t get as crisp. Stick with thin if you want crunch.

Try More Recipes:

• Mary Berry Halloumi and Sweet Potato Fries
• Mary Berry Chilli Burgers
• Mary Berry Fillet Steak With Peppercorn Sauce