In a large saucepan melt butter, cook onions until soft. Add mushrooms. Cook until soft.
In a large heavy saucepan, heat broth add thyme, add onions and Mushrooms cook until tender until tender, about 5 minutes.
In blender or food processor, puree the mixture , leaving some chunks of vegetable in it. Set aside.
In the saucepan, melt the butter, whisk in the flour until smooth. Add the salt, pepper, half and half, quinoa rice and vegetable puree. Stirring constantly, bring soup to a boil and cook until thickened. Adjust seasonings to taste, and add sherry and truffle oil.