An essential ingredient in Korean cuisine, gochugaru (or kochukaru) is a coarsely ground red pepper with a texture between flakes and powder. Traditionally, gochugaru is made from sun-dried chile peppers, and versions that are prepared in this manner are still considered the best tasting. The flavor is hot, sweet, and slightly smoky.
So now that you know what it is.
Go and use it in your next meal.