Potato and Mushroom Gratin

This nice little recipe is from Nigella's 'Express' cookbook, and is a good accompaniment to roast chicken or, in our case tonight, a proper veal saltimbocca.  Not too creamy, it uses milk rather than cream and not very much butter, so not too naughty - deeply mushroomy, too.  For 4 people, you need to peel and thinly slice 3 medium-ish potatoes - go for Maris Piper or King Edward's.  Heat 360ml of milk in a pan, along with 3 tablespoons of white wine (don't miss this bit out, it really lifts the flavour).  Season well with salt and pepper.  Add the sliced potatoes and simmer gently whilst getting on with the mushrooms: slice 250g of chestnut mushrooms and saute in a frying pan in 25g of butter and a grated or crushed clove of garlic.  I added some fresh thyme at this stage, because I had some, along with a grating of nutmeg because - well, life is better with nutmeg!  Once the mushrooms have sauteed for a few minutes and given off some of their liquid, tip the contents into the pan with the milk and potatoes and stir well.  Pour all of this into a buttered shallow gratin dish, smooth the top, grate over a little parmesan and bake at 180 for about 30 minutes until the potatoes are tender, most of the milk has been absorbed and the top is lovely and crusty brown.   As there were only 2 of us we have some leftover, but I think they will reheat well tomorrow - if I can stop picking at the dish in the kitchen.......oh dear!