Eierlikoer

One way to use up leftover egg yolks. Eierlikör recipes vary a lot. Some use cream, others condensed milk. Ratios of sugar, alcohol, cream, eggs vary widely.
Eierlikör is shelf stable when alcohol content is at 18% or higher.

4 egg yolks
125 g of sugar
125ml cream
125ml Rum or Cognac or any good alcohol that is neutral or pairs well with egg and cream
1 vanilla bean or equal amount of vanilla sugar, extract, paste …
If desired other spices lis nutmeg, cloves, cinnamon can be added to taste.

Mix all ingredients and heat slowly to 65 degree C (149 degree F) while consent whisking. Best is to use a double boiler (Bain-marie) to avoid cooking the mixture.
Recipe make a bit less than 1.2liter. Ok to tipoff a bottle with some more cream and alcohol as long as the alcohol ratio is high enough to make it shelf stable.

Adaption from this recipe
www1.wdr.de/verbraucher/rezepte/heimathaeppchen/eierlikoer-112.html