My own method, which seems to work on my fairly light sandy loam.
Earth up violently - 9" or more. If planted at 2-3ft centres, this leaves a considerable trench. Lay 2/3 in of unrotted but aged bedding from rabbit & hen house cleanings down the trench, and water the mulch. Watering tops or batters tends to bring the roots to the surface, where a) they dry out b) they produce surface tubers which go green & poisonous.