With over 2.12m searches for “sweet potatoes” on TikTok in the last couple of weeks, it seems the UK is suddenly obsessed with the nutrient-dense carb.
Mimi Morley, senior recipe development manager at HelloFresh, the world’s leading recipe box provider, reveals the definitive hack to achieve the elusive “gastropub crunch” and a deep, natural caramelised glaze that transforms the vegetable from a side dish into the star of the show.
According to Mimi, the biggest mistake home cooks make is taking the potato straight from the chopping board to the oven.
“People often treat sweet potatoes exactly like Maris Pipers, but they are a completely different beast chemically,” says Mimi. “They have a much higher sugar content and a different starch structure. If you want that crisp exterior without the soggy middle, you have to start with a cold-water soak.”
After cutting your potatoes into wedges or fries, Mimi recommends soaking them in cold water for at least 30 minutes.
“This draws out the excess surface starch,” Mimi explains. “Surface starch is what causes potatoes to stick to the pan and turn into a gummy mess. By removing it, you allow the heat to hit the structure of the potato directly, creating a structural shell that crisps up beautifully.”
Mimi also has a tip to achieve the perfect caramelised glaze which involves mastering the Maillard reaction – the chemical process that creates that golden-brown, savoury-sweet crust.
“The mistake people make with the glaze is adding honey or maple syrup too early,” Mimi warns. “Because sweet potatoes already have high natural sugars, adding more at the start of a 200°C roast will just result in burnt edges and a bitter taste.”
“For the perfect glaze, the key is to remove the moisture,” Mimi adds. “After the soak, you must pat them bone-dry with a tea towel. If they’re damp, they’ll steam, not roast. Roast at 200°C (or 180°C Fan). Halfway through, give them a toss. This is when the natural sugars begin to seep to the surface and caramelise into that signature sticky-sweet glaze.”
Mimi adds, “For an extra layer of ‘glass-like’ crunch, toss your dried wedges in a light dusting of cornflour and smoked paprika before adding oil. It creates a thin batter-like interface that holds onto the glaze.”
