I don't know where I got this recipe ... one of those things you just make over and over ... too many years to remember. It certainly makes an elegant dish out of the common russet potato. And it's a wonderful dish to carry to a potluck! It's perfect with pork.
2 large shallots, diced and sauteed in 3 T. butter
1# Russet potatoes, sliced
2/3 C. Parmesan cheese
1 peeled and sliced celery root
1 T. Herbs de Province
salt & pepper to taste
Layer in a buttered gratin or casserole dish. Bake at 350 degrees for 25 minutes – then turn up to 425 degrees and continue cooking for another 25 minutes.