Long time no see. I'm just writing quickly to make a note of this week's exciting new recipe.

We don't generally eat many potatoes here, because they are not good friends with S's pancreas. However! I recently discovered that celery root is absolutely delicious*, and it turns out that it is also S-friendly. It was obvious from the start that it would work nicely in a gratin. Then the works of Deborah Madison soon gave me to know that it is, furthermore, good with hazelnuts and mushrooms, and the recipe below was born. We will be having this again very soon indeed.

*Even though I don't particularly like celery qua celery.

CELERY ROOT AND PARSNIP GRATIN
1 large celery root (celeraic)
2 medium parsnips
2 tablespoons butter, plus extra for the baking dish
3 tablespoons flour
2 cups milk
2 minced cloves of garlic
1 small onion, chopped
1 large carrot, grated
salt to taste
about 1 teaspoon porcini powder (optional but highly recommended)
1/4 cup finely chopped nuts, preferably hazelnuts
some parmesan cheese

Put a nice big pot of salted water on to boil, and preheat the oven to 375°F. Peel the celery root and parsnips and cut into slabs about 1/3" thick. I cut the celery root into several pieces, first, to get slices about two inches across, and cut the parsnips on the bias, so they were more or less all of a size. Put into a bowl of acidulated water -- lemon or vinegar will do equally well -- until the water is boiling and you're ready to deal with them again.

Meanwhile, make a bechamel sauce: heat the butter in a suitable pan, then whisk in the flour and cook, stirring constantly, for 2-3 minutes. Reduce the heat to low and add the milk in a stream, whisking all the time (you can warm the milk first, which does make things go more smoothly at this stage, but I don't enjoy dirtying a third pot, and I have faith in my whisking skills). Add the garlic and onion and cook for a while, stirring often with your whisk, until it's nice and thick, at least as thick as heavy cream. Stir in the grated carrot. Salt to taste and set aside.

Drain the vegetables and add to the boiling water. Cook for 5 minutes and drain. Butter your baking dish and put the vegetables in it. Shake the porcini powder over top, if using. Pour the bechamel over top. Sprinkle the chopped nuts over top and grate some cheese over that.

Bake for about 40 minutes, until bubbly and browned on top.