Heat most of the butter in a shallow pan.
Add the shallots, bay leaf and thyme, and
cook for 10 mins until soft, golden and
sticky. Pour in the cream and bring to
the boil. Turn off the heat, season with
nutmeg and cayenne and leave to infuse.
Meanwhile, heat oven to 200C/180C fan/
gas 6. Place the potatoes in a pan of cold
water, bring to the boil, then drain. Butter
a large gratin dish, then layer it up with
potatoes and cream, finishing with a
good ladle of cream and shallots. Use
a fish slice to press everything down.
You can now cover and chill it for up to
a day before baking, if you like. Bake for
40 mins or until golden and the shallots
are starting to crisp.