Preheat the oven to gas 6, 200°C, fan 180°C.
Cook the potatoes in a large pan of boiling salted water for 15-18 minutes, or until softened.
Drain the potatoes and transfer to a roasting tin.
Using the back of a wooden spoon, gently crush the potatoes, until slightly flattened.
Drizzle over the olive oil, season well and toss with the garlic and the thyme leaves.
Roast for 20-25 minutes, or until crispy and golden.
