Peel, rinse and cut potatoes into pieces. Boil potatoes in salted water until tender, about 25 minutes. Drain and let cool.
Press warm potatoes through a potato ricer and immediately mix in butter, egg yolks and flour. Season with salt, pepper and nutmeg. Peel garlic and press through a garlic press into mixture. Mix in cilantro leaves. Mixture should hold together; it shouldn't be too wet or too dry. If necessary, mix in an additional egg yolk or flour.
Form mixture into short, inch-thick croquettes and roll in sesame seeds. In a frying pan, heat clarified butter. Fry croquettes in batches until golden.