Boil the potatoes in salted water for about 10 minutes, then drain and transfer to a wide baking dish. Cut them into 1/2 inch cubes and sprinkle over some salt and pepper, the olive oil and the garlic. Mix and turn the potatoes so they are coated all over with the oil.
Roast the potatoes in a very hot oven, preheated to 475 degrees, for 30 minutes, or until they are crisp and brown. Remove potatoes and sprinkle evenly with the lemon juice and chopped coriander, and mix well (being careful not to break the potatoes).