During flambé, what is the powder that is shaken into the fire to create sparks? My apologies for a lack of link, although hopefully my description will suffice. I saw some transient video of chefs making Bananas Foster in, I believe, New Orleans. They were shaking a powder into the flames to produce a dramatic sparks effect. What is this powder? I can't find any YouTube videos of it, so I believe it might be a lesser-known, regional flourish. At any rate, it looked spectacular and I would recommend it to anyone flambé-ing in front of an audience.
just a cinnamon or cinnamon blend with nutmeg and other spices will make sparks when tossed into the fire.

You do need a big flame for this; I typically use a camp chef stove with a modified propane regulator to get the big flame needed.