Slice potatoes (unpared) thinly, using a food processor if desired.  Slice onions thinly, again using a food processor if desired.  Grease a casserole dish and layer the potatoes, onions, lentils, and chestnuts, ending with a layer of potatoes and salting and peppering each layer.  Pour broth over the top layer of potatoes, dot with margarine, and cover.

Bake at 350 degrees for one hour, until potatoes are tender.  Remove lid, raise oven temp to 400, and bake another 10-15 minutes, until potatoes are crispy and browned.

Note:  You can use fresh chestnuts, baking them and peeling them yourself...but only if you're really masochistic!  Since I discovered canned ones, I would never attempt to peel another chestnut for love or money!

Serves 4-6.