Mixed mushroom & tarragon gratin

Put the dried mushrooms in a mug or small heatproof bowl and pour in 150ml just-boiled water. Cover and set aside. Tear the oyster mushrooms from the mixed pack in half and halve any large shiitake. Halve any of those mushrooms with a similar diameter to a golf ball, quarter any slightly smaller ones and leave the smallest whole.

Divide the butter into three equal pieces. Put one in a large frying pan, place over a high heat and arrange the mixed woodland mushrooms in one layer. Fry without touching for 60-90 seconds so they begin to turn golden, then flip the mushrooms one by one and colour for 60 seconds more. Transfer to a 2L ovenproof gratin dish. Add the second piece of butter and half the chestnut mushrooms to the pan. Repeat the quick browning process, but do not cook for more than 3 minutes. Finish the final batch and transfer to the dish. Strain the reconstituted mushrooms, reserving the liquid. Add the mushrooms to the gratin dish and mix.

Return the unwashed frying pan to a high heat. Add the mushroom soaking liquid, cream and garlic, bring to a boil and reduce by half over 3 minutes or so. Remove from the heat, stir in the Parmigiano Reggiano and add the lemon juice, tarragon and season well with salt and pepper. Pour over the mushrooms and mix again. If not cooking immediately, leave to cool and refrigerate for up to 24 hours.

Preheat the oven to 220ºC, gas mark 7. Tear the ciabatta into thumbnail-sized pieces (don’t cut away the crust). Toss with 1-2 tbsp olive oil, until all surfaces of the bread are glossy, plus a good pinch of salt. Arrange over the mushrooms then bake for 20 minutes until the sauce is bubbling and the bread is golden. Scatter with extra tarragon to garnish.