It is glazed inside. The way that the lid is made, and fits, doesn’t really allow for something perishable to be put inside and sealed. The powdered sugar won’t work because the words aren’t embossed. It is bugging the you know what out of my wife and I. We have googled every possible combination of words we can, and looked through a lot of images in order to figure it out. I don’t think it is old, so it has to be “right in front of us” but we can’t figure it out. I will post if we figure it out.