Sweet Potato Tuscan Fries

Our answer

Nigella's method for cooking Tuscan Fries (from NIGELLISSIMA) is slightly different to regular fries as the cut potatoes are put into cold oil. The oil is then heated and the potatoes cook as the oil heats up. The fries come out crisp and dry and not greasy. This method works best with a waxy type of potato and for this recipe there is no need to rinse or soak the potatoes with water before cooking as the potatoes are started in cold oil so the starches on the outside will cook to a crust at the same time as the inside of the potatoes cook through.

Sweet potatoes have a lower starch content and a higher sugar content than white potatoes. This means that they don't tend to form the same crisp crust when fried vs a white potato. We don't necessarily think that they will absorb more oil but the fries will likely be softer and limper than white potato fries. In addition, due to the higher sugar content, sweet potato fries could brown more quickly than white potatoes and could need a shorter cooking time. They should be watched more carefully to make sure that they don't burn. On balance we prefer to stick with white waxy potatoes for this recipe.