Preheat the oven to 180C/350F/gas 4. Wash the potatoes and scrub if they need it, chop larger ones in half. Put them into a casserole dish with a lid, about 20cm, add the garlic cloves, peppercorns, sprinkle over the salt and tuck the lemon slices and thyme sprigs in between the potatoes. Pour over the oil, there should be enough to almost, but not completely, cover them.
Put the lid on and bake for 1 – 1 ¼ hour, check with the tip of a knife if the potatoes are tender. let them stand, covered, for 10 minutes, then drain off the oil or scoop the potatoes and the garlic out of the oil into a serving dish.
You can serve them with stir-fried spring cabbage (http://www.cuisinefiend.com/169/stir-fry-cabbage) for a wholesome vegetarian supper.
