Whisk gelatin with water and set aside. In a large saucepan over medium heat, whisk next 7 ingredients (through nutmeg); cook until mixture almost comes to a boil. Remove from the heat; whisk in gelatin mixture, pumpkin and vanilla. Strain through a fine mesh strainer into a large spouted measuring glass or pitcher; discard solids, if any. Pour evenly into 6 (6-8 oz.) ramekins; refrigerate until firm (4-48 hrs.), covering with plastic wrap once cool. To serve, dip the bottom of each ramekin in hot water up to the rim, then run a knife around the edge; invert onto a serving plate. Serve drizzled with syrup and sprinkled with nuts.