Crisp From the Oven, With a Flaming BBQ Dip

When I was a boy in Guadeloupe, nobody called them sweet potato fries, and sweet potato was never a treat. It was just there. Patate douce, we call it, and it came home from the market in the same basket as the yams and the green bananas, with the earth still on the skin. My mother boiled it for the Sunday colombo, mashed it with butter for the little ones, and sometimes, when there was oil in the pan from frying fish, she cut a few slices and dropped them in.

Those were the best. Thin coins of sweet potato, dark at the edges, soft in the middle, salted the second they came out. Seven children around one plate. You learned to be quick.

When I came to England I found sweet potato fries on every pub menu, and I was very happy, until I ate them. Soft. Bendy. Sad. Sitting in a basket going limp while you look at them. People told me sweet potato fries cannot be crisp, that it is just the nature of the thing. I do not accept this.

They can be crisp. You need three things: a little cornflour, a very hot tray, and space. That is the whole secret, and I will show you each part.

And then you need something to dip them in. Sweet potato is sweet, so it wants heat and a bit of sharpness against it. For me that is a spoon of my Flaming BBQ Sauce stirred into mayonnaise with a squeeze of lime. Two minutes. The tray goes in the oven, the dip goes in the fridge, and supper is nearly done.

Recipe at a glance

• Cuisine: French Caribbean (Guadeloupe)
• Prep: 10 minutes • Cook: 30 minutes • Total: 40 minutes
• Serves: 4 as a side
• Featured sauce: Flaming BBQ Sauce
• Heat level: 8/10 in the dip, 0 in the fries, so everyone takes what they want
• Diet: Vegetarian, gluten free, dairy free (use a vegan mayonnaise and it is vegan too)

What you’ll need

Choose sweet potatoes that are long and even, not fat and knobbly. They cut into neater batons and cook at the same speed. I leave the skin on. It crisps beautifully and it saves you five minutes of peeling.

For the fries

• 800g sweet potatoes (about 3 medium), scrubbed, skin on
• 2 tbsp cornflour
• 1 tsp sweet paprika
• 1/2 tsp garlic powder
• 1/2 tsp dried thyme
• 1/4 tsp ground allspice
• 3 tbsp sunflower or vegetable oil
• 1 tsp flaky sea salt, to finish
• 2 spring onions, finely sliced, to finish

For the Flaming BBQ dip

• 4 tbsp mayonnaise (or a vegan mayonnaise)
• 2 tbsp Full Feast Flaming BBQ Sauce, plus extra for the brave
• Juice of 1/2 lime, plus wedges to serve

How I make it

1. Heat the oven and the tray. Put your largest baking tray (or two trays) in the oven and heat it to 220°C (200°C fan). The tray must be hot before the potatoes touch it. This is where the crust starts.

2. Cut the batons. Trim the ends of the sweet potatoes and cut them into batons about 1cm thick and 8 to 10cm long. Try to keep them the same size. Thin ones burn while thick ones are still soft, and then you blame the potato.

3. Rinse and dry them properly. Rinse the batons in a colander under cold water for a minute to wash off the loose starch. Now tip them onto a clean tea towel and rub them dry. Really dry. Water is the enemy here, it steams them instead of frying them in the oil.

4. Coat in cornflour first. Put the dry batons in a large bowl, add the cornflour, paprika, garlic powder, thyme and allspice, and toss with your hands until every piece has a thin, dusty coat. No salt yet. Salt pulls the water out and you will lose the crunch.

5. Then the oil. Pour over the oil and toss again until the powder turns into a light paste on each baton. If you see dry white patches, rub them in.

6. Give them space. Take the hot tray out, line it with baking paper if you like, and spread the fries out in one layer with a little gap between each one. If they touch, they steam. If you need two trays, use two trays. I promise you this matters more than anything else in this recipe.

7. Roast and turn once. Roast for 15 minutes without opening the door. Then take the tray out, turn the fries with tongs or a spatula, and swap the trays around if you are using two. Roast for another 10 to 15 minutes, until the edges are deep brown and they sound hard when you tap one with a fork.

8. Make the dip while they cook. Stir the mayonnaise, Flaming BBQ Sauce and lime juice together in a small bowl. Taste it. Want more fire? Another spoon of sauce. Keep it in the fridge until the fries come out.

9. Let them rest, then salt. Leave the fries on the tray for 3 to 5 minutes once they are out of the oven. They firm up as the steam escapes. Then scatter over the flaky salt and the spring onions while they are still hot, and serve straight away with the dip and lime wedges.

The role of Flaming BBQ Sauce in this dish

Sweet potato fries are sweet, a little earthy, and soft inside however crisp you get the outside. They need a dip that pushes back.

My Flaming BBQ Sauce starts as my BBQ Sauce: tomato purée, brown sugar, balsamic vinegar, a splash of rum, garlic and English mustard. Then I add real chilli. In the mayonnaise that means three things happen at once. The tomato and sugar meet the sweet potato like old friends. The balsamic and mustard cut through the richness of the mayo. And the chilli arrives a second later, warm at the back of the throat, so you reach for the next fry to cool down, which of course does not work.

That is the whole point. You dip, you feel the heat, you dip again.

Tips from my kitchen

• Cornflour, not flour. Cornflour makes a thin, glassy crust. It is also why this side is gluten free. Two tablespoons is enough, more and they taste chalky.
• Do not crowd the tray. I say it again because everybody does it. If the fries are piled up, you are steaming them. Two trays, always.
• Salt at the end. Salt before cooking draws out water and makes them soft. Salt the second they come out.
• Keep the skins. The skin holds the baton together and goes lovely and crisp at the corners. Just scrub it well.
• Use the dip twice. That same Flaming BBQ mayonnaise is very good spread inside a burger or a chicken wrap the next day. And if you love a creamy dip with a kick, try my spicy mayo with Caribbean Hot Sauce for a different kind of heat.

What to serve it with

Sweet potato fries are made for sharing, and they sit happily next to almost anything from the grill or the oven.

At my house they go next to a Caribbean BBQ burger, juicy and sticky, with the dip doing double duty as burger sauce. On a Friday night with friends I make a tray of these alongside my Flaming BBQ chicken wings and let everybody fight for the last ones.

If you want a whole table of fried things, put them out with my plantain chips and a plain green salad dressed with lime. Sweet, salty, crunchy, hot. That is a good evening.

For a lighter plate, serve them with grilled fish or a piece of roast chicken and a simple tomato and cucumber salad.

FAQ

How do you make sweet potato fries crispy in the oven?

Three things. A thin coat of cornflour, a tray that is already hot at 220°C, and enough space that no two fries touch. Turn them once halfway, and leave them a few minutes on the tray before salting. Do those and you will not go back.

Why are my sweet potato fries soggy?

Almost always one of these: the batons were wet when they went in, the tray was crowded, or they were salted before cooking. Sweet potato has more sugar and more moisture than an ordinary potato, so it steams very easily. Dry them well, give them room, and salt at the end.

Can you make sweet potato fries in an air fryer?

Yes, and they come out very well. Coat them exactly the same way, then cook at 200°C for 12 to 16 minutes, shaking the basket every 5 minutes. Do them in batches so the basket is never more than half full. Same rule as the oven: space is everything.

Can you freeze sweet potato fries?

You can freeze them raw once they are cut. Blanch the batons in boiling water for 2 minutes, cool them, dry them, then freeze on a tray before bagging. Cook from frozen with the cornflour and oil at 220°C, adding 5 to 10 minutes. Cooked fries do not freeze well. They lose the crunch and I would rather you ate them all on the day.

Are these sweet potato fries gluten free, and what about allergens?

The fries and the dip are gluten free as written. Cornflour is naturally gluten free, and all six Full Feast sauces, including the Flaming BBQ, have tested gluten free. Please know the dip contains egg (in the mayonnaise) and mustard (in the Flaming BBQ Sauce). The sauce also contains sulphites from the balsamic vinegar. Use an egg-free mayonnaise if you need to.

Final word from me

My mother never measured anything, and her sweet potato never went soft. It was the hot oil, the space in the pan, and the salt at the very end. I have just written it down for an oven. Make one tray this week, keep the dip hotter than you think you want it, and see how long it lasts on the table. Not long, I think.

JP