I'm writing a play in which a bakery is being used as a front to smuggle heroin, unbeknownst to the women running the bakery. I need to have one of my characters (who is NOT an experienced baker) accidentally use the heroin in place of another ingredient while baking.
Setting/time period: Unsure, just yet, but sometime within the last few decades.
Google-fu'd: Erowid, "heroin," "heroin consistency and texture," multiple pictures of heroin.
Prior knowledge: I've baked a decent amount from scratch, so am relatively familiar with the primary ingredients used in baking, but if there are any less-conventional ingredients or spices any bakers use that could work, that would be helpful too!
Looking at pictures gives me a general idea of what ingredients heroin (more specifically white powder heroin) may be similar enough to to make the mistake, but having never seen the stuff in person, I thought I may see if anyone has a little more knowledge or experience that could help me.
The specific baked good is more up to what works best; it could be cookies, cakes, pastries, breads, whatever.
I need an ingredient that heroin could be conceivably substituted for with no visible effects; it doesn't matter if the taste is off.
So, I've already preliminarily ruled out baking powder/soda (and therefore, cream of tartar), due to how the absence of either of those ingredients could affect how the goods turn out after baking (unless there is a recipe where only the taste/texture of a baked good is affected by a lack of baking powder/soda).
Would powdered sugar be too much of a stretch?
Any thoughts or suggestions would be greatly appreciated!