I was at a craft show in Tennesee back in October and saw some monogrammed coasters made from ceramic tiles. Does anyone know what I'm talking about and how to make them? They looked like kitchen/bathroom tiles (4x4) with initials painted on them and then sealant.

The lady told my sister-in-law it was more difficult than it looked and required baking the tiles a couple of times and so on.

Any help? I wanted to make some for my in-laws for Christmas!