Chestnuts can now be bought in vacuum tins or bags, ready peeled and cooked - much more convenient than having to do the job yourself.
Bring a pan of salted water to the boil and cook the sprouts for 8-10 minutes. Meanwhile, roast the chestnuts in a little of the butter in the oven or under the grill. Drain the sprouts and toss with the chestnuts in the remaining butter. Season to taste.