Set sous vide machine to 80C/176F.

In a large bowl, whisk egg yolks together. Add eggnog and whisk again until smooth.

Pour an equal amount of eggnog filling in each canning jar, and screw on the lid of each jar (see note). Gently submerge the entire jars in the bath using rubber tongs, and set a timer for 1 hour.

Remove from bath and let rest on counter top for 30 minutes to cool. Once cooled, transfer the eggnog custards to the refrigerator for a minimum of 8 hours to set the custard. When ready to serve, garnish with the crust (recipe below) and a shake of nutmeg. Now enjoy this heavenly custard straight from the jar!

Preheat oven to 163/325F.

In a food processor, pulse graham crackers until finely crushed. Add sugar and cinnamon and mix until ingredients are combined. Slowly pour in melted butter to mixture while pulsing. Alternatively use a bag to crush the graham crackers then stir in the sugar, cinnamon and butter by hand if you don't have a food processor!

Spread mixture in an even layer on a lined cookie sheet. Bake for 15 minutes, stirring halfway through.

Remove crust mixture from oven, and set aside to cool.