This is an old, nearly extinct local dish that intrigues me, especially after Arnaud’s revived it for a while. After failing a couple of times to get it right, I came up with this, which I now serve at Thanksgiving in place of plain old peas.
Make a blond roux by melting the butter in a saucepan over medium heat. Add the flour and cook, stirring constantly, until the mixture just barely begins to brown. Lower the heat to almost nothing. Add the mushrooms and green onion, and stir lightly to blend into the roux. The heat of the roux will cook the mushrooms and onion, and the vegetables will bring down the heat