Preheat the oven to 245 degrees Celsius/220 degrees Celsius fan/475 degrees Fahrenheit/Gas 9.

Add the potatoes to a large saucepan. Cover them entirely with water and add the salt – this helps to remove the starch. Bring to the boil and cook over a high heat for five to 10 minutes. You will know the potatoes are done when the water starts to foam (or the water begins a rolling boil). The fries should be soft but still firm to the touch.

Remove from the heat and drain the fries, washing them in cold water using a sieve. This stops the fries overcooking.

Transfer the fries to a roasting tin and add the garlic and thyme. Drizzle with olive oil until the fries are well coated, then add 50 milliliters/three and a half tablespoons water.

Cover the roasting tin with foil, then roast in the preheated oven for 30–40 minutes until the fries are soft and slightly charred. If the potatoes are not charred after 30 minutes, remove the foil, return them to the oven and let them crisp. Serve hot and enjoy with your favorite dipping sauces.