Iíd love some help with my attempted murder, please!

I need a poison that could be found in a modern-day restaurant kitchen. It has to be something that could be mixed into a drink (currently itís a hot chocolate with peppermint schnapps, though itís not terribly important what kind of drink) and drunk by the unsuspecting victim, who then succumbs fairly quickly, over the course of the conversation over the drinks.

My poisoner is originally from the early 1900s and has gotten herself a job as a waitress in this restaurant, present-day. I was hoping to find some kind of Victorian-era poison, or something they used to use regularly that we now just consider poison, but could still be stocked in a kitchen (Laudanum, arsenic, something like that? Those are still in some cleaning agents, right?). I currently have it written as two shakers of unknown (to me) spices that, when combined, are deadly (because that sounds pretty cool), but I have no idea if thatís in the realm of reality, or what spices those could possibly be.

I was reading about cyanide in apple seeds and cherry pits and thought maybe if she crushed enough of those up into the drink, it could work. But it seems like I would need a LOT of apple seeds, and cherry pits are pretty hard to crush, especially discreetly...

So Iím open to any other ideas, thanks!