In a medium bowl set over a saucepan of simmering water (or a double boiler) heat egg yolks and evaporated milk, whisking constantly, until mixture is thick enough to coat the back of a spoon (about 160 degrees).
Transfer egg mixture to a blender, along with cream of coconut, condensed milk, rum, cinnamon, and vanilla. Blend for about 30 seconds. Pour into a covered pitcher and refrigerate overnight. When ready to serve, stir the punch and pour into glasses.
Recipe by Three Many Cooks at https://threemanycooks.com/conversations/adriannas-puerto-rican-egg-nog/