Pour the evaporated milk and half and half into another bowl and stir to combine. Set aside.
Place eggs and sugar in a medium bowl and whisk until thoroughly combined.
Transfer to a saucepan and stir in whole milk, vanilla extract, and ground nutmeg.
Heat egg mixture over medium-low heat while stirring constantly to prevent the milk from scorching. When the mixture reaches 160F/71C on a candy thermometer, remove from heat and slowly whisk in evaporated milk mixture.
Cool slightly before tasting. Add more sugar or nutmeg, if desired, before transferring to an airtight container.
Refrigerate overnight or until thoroughly chilled.
Serve in mugs and garnish with whipped cream, cinnamon sticks, and/or a dash of nutmeg, if desired. Enjoy and Happy Holidays!