Over medium heat in a large skillet add the butter and olive oil. When butter is melted add the mushrooms, onion and garlic. Cook for 5 minutes, stirring occasionally unit mushrooms are soft.
Sprinkle the flour over mushroom mixture, stirring to cook for 2 minutes. Whisk in the chicken stock, then the cream. Cook for 3 minutes on simmer. Season to taste with salt an pepper. This will be thick.
Use as you would a can of condensed cream of mushroom soup. If not using right away, allow to cool and store in an airtight jar and refrigerate. Makes 1 1/2 cups, the equivalent of a 15 ounce can of condensed soup.
Notes
This recipe makes the equivalent of one can of Campbell's cream of mushroom soup. Feel free to double the recipe if desired.