Heat oven to 180C/160C fan/gas 4. Tip potatoes into a large roasting tin. Add the olive oil, bay leaves, garlic and thyme, stir and season well. Put potatoes in the oven and roast for 30 mins (the final 30 minutes of the beef if you are cooking as part of a roast - see 'Goes well with' recipe, right).
While meat rests, turn up the heat to 200C/180C fan/gas 6. Shake the roasting tin and continue to cook the potatoes for 30 mins more until golden and crisp.