Ah, the lovely and sensible Jane Grigson.
So, for this gratin I borrowed the proportions of veg to liquid from Jane and used whatever veg I had in the garden. It totalled a kilo; 600g potato and the rest in sorrel and young courgettes. I did not peel the potatoes because the peeler has disappeared. But this made the gratin event better, the edges a chewy bonus, a bit of texture in the creamy veggie goo.
For 1kg veg I used 400ml liquid, half and half veg stock and cream.
For flavouring I used 3 cloves garlic and lemon thyme flowers (because the thyme had flowered, not because I was being deliberately posh). And loads of black pepper.You just slice the veg to the thickness of a 50p piece and layer with the flavoured bits, and then pour the mixed liquid on top.
I baked at 200 degrees c for 55 minutes and the gratin was delicious. I mopped the creamy sauce up with bread. A big carb fest love in. Yuuuum.
Oh, and sometimes the liquid is hard to get right in a gratin. You need it to practically cover the veg, but yet not to be liquid at the end. If its too liquid just ladle some out at the end of cooking and pop the gratin back in the oven for 5 mins.