This will impress your Shabbos guests to no end and is ridiculously easy.
4 egg yolks
1¼ cup sugar
1¼ cup water
3 Tbsp coffee
1 (212 ml) rich's whip
1 tsp vanilla extract
½ cup 95% pure alcohol
Combine all ingredients and mix in a food processor until smooth
Refrigerate for at least 24 hours before serving (this is so the consistency can get thicker in the fridge).
(For Shabbos, I like to serve it in a nice glass or decorative bottle)
*** IMPORTANT: If you choose to dilute the coffee in hot water, mix in some cold water because you don't want to pour hot water on the egg yolks, as it will cook them.