In a large skillet, melt butter. Add onion, garlic. Saute until tender but not browned. Add tarragon, stir until it is softened. Pour mixture into food processor. Add Mushrooms and remaining ingredients. Process until mixture is smooth. Add cheese if you prefer a more spreadable consistency. Spoon into a serving bowl. Top with garnish of your choice. Serve with crackers, thick slices of crusty French bread, thin slices of whole wheat bread, or unsalted whole wheat crackers. May be frozen. Makes 1 1/2 cups.
