Blend everything in a food processor or blender, in batches.
For an extra creamy texture, push the puree through a sieve with the back of a ladle.
Stir in the rest of the cream. (If preparing ahead cool, cover and chill for up to a day.)
To serve, pick over the mushrooms. Wild mushrooms can be gritty so wash them quickly in a bowl of cold water then drain well and pat dry.
Trim the stalks and chop or slice the mushrooms neatly.