Kevin Gratton, my group head chef, encountered some logistical problems with this dish that we served at the opening night cocktail party at Stephen Webster's new shop. Firstly, I forgot to tell Kevin that heavy cream in the States doesn't behave like our double cream and it ends up separating, so we had to do a bit of culinary doctoring to get the topping right. Secondly, Kevin left the pastry bases for this dish in the oven as we were on our way to Stephen's shop and they got burnt to a cinder, so we had to think on our feet and decided to use some thin lavash bread (Middle Eastern flatbread), which happily worked a treat. Kevin is still being gently teased about the hiccups in LA, but this delicious tart with the lavash bread has ended up on our menu in London and it's a great simple solution for a dinner-party tart. Cheers, Kev, this one's named after you!
1 large leek, halved, cut into rough 1cm dice and washed
250g oyster or button mushrooms, sliced
A couple of good knobs of butter
Salt and freshly ground black pepper
250ml double cream
150g freshly grated Parmesan
50g fresh white breadcrumbs
A piece of flatbread or a flour tortilla about 30cm in diameter
Preheat the oven to 220C/gas mark 7. Melt the butter in a heavy-based saucepan and gently cook the leeks and mushrooms for 3-4 minutes with a lid on without colouring. Add the double cream and two-thirds of the Parmesan, season and simmer until the cream has reduced and is just coating the leeks and mushrooms.
Put the flatbread on to a baking tray and spread the leek and mushroom mix over, then scatter over the breadcrumbs and the remaining Parmesan. Bake for about 10-12 minutes until lightly coloured and serve immediately.