In a saucepan, bring the water to a boil and add the Brussels sprouts. Return to boil, reduce heat, cover, and simmer 5 to 7 minutes, until sprouts are tender. Drain.
In a microwave safe bowl, mix the butter, walnuts, brown sugar, allspice, nutmeg, and salt. Cover, and cook on High 3 to 4 minutes, stirring occasionally, until the butter is melted and the walnuts are warm. Pour over the cooked Brussels sprouts to serve.
