I didn't know until recently that there are many species of cinnamon. What I was familiar with was cassia cinnamon, which is used as commercial spice. Apparently 90% of what we buy at the market is cassia cinnamon. This is what we sprinkle on our coffee cakes and desserts.
Cinnamon comes from the inner bark of a cinnamon tree; the bark is ground up. This spice has been used for thousands of years.
