Pour the half-and-half, dry milk, and milk into a large saucepan over low heat. Cook until heated, stirring to dissolve the dry milk. Stir in the peanut butter and sugar until smooth and sugar has dissolved. Remove from heat, and stir in the vanilla. Cool mixture, and refrigerate.
Stir the mixture, or blend in a blender before pouring into an ice cream maker. Freeze according to the manufacturer's instructions.