Peel and cut the potatoes into 2cm cubes. Try to make them all roughly the same size, but it's not necessary to get a ruler out and measure them...like my husband did the other day!
Bring a pan of salted water to the boil and cook the potatoes for 4 minutes (set the timer from when they went into the boiling water). Drain into a colander and allow them to steam dry but DO NOT SHAKE them.
Whilst the potato cubes are steam drying, preheat the oven to 200c (180 fan/ Gas 6). Pour the olive oil into a roasting tin and place it in the oven to heat up.
After 5 minutes, remove the roasting tin from the oven and tip the dried potato cubes in. Carefully use a spoon to turn the potatoes in the oil, making sure they are coated. Do this gently to prevent the potatoes from breaking up. Season and place in the oven for 20 minutes.
Peel and chop the garlic and finely chop the rosemary and thyme leaves. Add these to the potatoes after 20 minutes (give the potato, garlic and herbs a gentle mix at this point). Return to the oven for another 15-20 minutes until lightly golden. If you prefer a darker more crispy potato you might want to leave them in for an extra 5 minutes.