Place potatoes in a large saucepan, cover generously with cold salted water and bring to the boil over medium-high heat. Cook until just tender (15-20 minutes), drain, refrigerate until chilled, then cut into 1cm-thick slices.
Heat one-third duck fat and one-third clarified butter in a large frying pan over medium-high heat until smoking. Carefully add half the potato in a single layer and cook, turning once, until dark golden (5-7 minutes). Remove potato, wipe pan with absorbent paper and repeat with half remaining fat and butter, and remaining potato. Wipe pan, heat remaining fat and butter over medium heat, add onion and stir occasionally until light golden (5-7 minutes). Add garlic, stir occasionally until golden (2-3 minutes), then add thyme and potato. Season to taste, toss through parsley and serve hot with confit lamb.
Note You’ll need about 75gm butter to yield 50gm clarified butter.
This recipe is from the July 2010 issue of Australian Gourmet Traveller.