In a large saucepan, heat milk to 180°; stir in brown sugar until dissolved. Remove from heat; whisk in spices, syrup and pumpkin.
Transfer to a large bowl; place bowl in a pan of ice water. Stir gently and occasionally 2 minutes. Stir in cream. Press plastic wrap onto surface of milk mixture; refrigerate several hours or overnight.
Fill cylinder of ice cream maker no more than two-thirds full; freeze according to manufacturer’s directions. (Refrigerate any remaining mixture until ready to freeze.) Transfer ice cream to freezer containers, allowing headspace for expansion. Freeze until firm, 2-4 hours.