How do I thicken Advocaat without evaporating any alcohol?
Use more of the thickener that is already in the advocaat: egg yolks.

Make a custard with egg yolks and advocaat, heating gently until it thickens, but not beyond 60 C / 140 F or you risk curdling. A water bath is safer than working directly on the burner. At that temperature, the loss of alcohol due to evaporation is limited.

You can add brandy (to boost alcohol content and liquify the yolks) and sugar to adjust the taste as desired. -> those are the base ingredients for advocaat, so you can toy with the ratios and consistency without changing the flavour profile.



If you want to use corn starch, use some starch to thicken either a portion of the advocaat or some milk or cream to a consistency way thicker than desired, let cool and dilute with advocaat until the desired consistency. (Or stir the "pudding" into the advocaat.)

In this case, you shouldn't let the corn starch mix get fully cold, or you'd destroy the binding by stirting too much - as this poster learned when making pudding.