Preheat the oven at 180C.
Clean all the mushrooms and roughly slice the bigger ones.
Place wild and shiitake mushrooms on a roasting tray, season with salt, pepper, olive oil and fresh thyme. Roast for about 50 minutes.
Meanwhile, heat a knob of butter in a pan, add the finely chopped shallot and allow it to cook for a few minutes until soft.
Add the chestnut mushrooms, season with salt and cook until soft.
Transfer all the mushrooms in a food processor and whizz into a smooth paste. Gradually add butter and cream until you get a creamy consistency. Taste and season as you go.
Heat the rest of the butter in a pan, on a very low heat, just until it begins to clarify and the milk solids remain at the bottom of the pan.
Transfer the wild mushroom pate into ramekins and add a layer of clarified butter on top. Decorate with thyme leaves and freshly ground black pepper.
Allow to set in the fridge for at least 6 hours (ideally over night).