EXTRACT: Place mushrooms in water in a saucepan & bring to a boil. Reduce heat & simmer for 15 minutes. Remove mushrooms with a slotted spoon & rinse. Chop finely & reserve. Strain extract.
SAUCE: Combine onions, water, tamari, salt, syrup, pepper & rosemary in a saucepan. Cover & simmer over medium heat for 5 minutes. Remove & discard parsley. Add extract & chopped mushrooms. Bring to a boil. Add arrowroot, cook & stir till thickened. Taste for seasoning. Use top rice, potatoes or pasta.