Folklore has it that the shot of alcohol burns a hole ("un trou") in your stomach so that you can eat more food. This is something we definitely could have used last Thursday!
At dinner parties, we tend to eat and drink throughout the evening, one conversation or platter of food simply rolling into the next. The idea of everyone pausing in the middle to sit back and sip a glass of special liquor has a nice air of ceremony. It's like a focal point for the evening to give guests a chance to regroup and resettle.
By the way, the traditional drink for a "trou normand" is calvados, an apple brandy from the Normandy region in France. These days, calvados is made following a strict formula, but we imagine that it started off a lot more rustic - and a lot more likely to literally burn that hole in your stomach!
We're curious how a trou normand actually works in practice. Does anyone have first-hand experience?