Cream of Mushroom Soup

1/2 onion 1 Tbls butter 1# mushrooms, sliced 1 Tbls salt 1 tsps pepper 1 qt chicken stock 1 qt milk 1 pt heavy cream White roux (about 1/4 # butter and 1/4  C. flour) 1 C. sherry wine or other fortified whine…porto, marsala, maderia Sweat the onions in butter. Add the mushrooms and continue to cook until they give up their liquid. Season with salt and pepper. Add the chicken stock and bring to a boil, reduce heat and simmer for 30 minutes. Add the milk, bring to a boil and reduce heat. Make roux and let cool slightly. Thicken the soup with the roux and reach desired consistency. Simmer for 20 minutes. Add the cream and the sherry. Adjust the seasoning. Add fresh herbs for garnish optional.