Heat the oven to 200C/180C fan/gas 6. Put the potatoes in a large pan filled with cold salted water. Bring to the boil and cook for 15 mins until a cutlery knife can be inserted into the centre of a potato with only a little resistance, then drain and leave to steam-dry.

Arrange the potatoes in a large shallow roasting tin, leaving enough space between each one so they have room to spread once smashed. Using the back of a large spoon or a fish slice, push down on each of the potatoes to make them crack open, then season. Heat the garlic and oil in a small pan and pour it over the potatoes. Roast for 1 hr, turning once, until golden and crisp, and serve with the stew.