Cut out the plastic clear part from a window envelope. Formed it and glued it into a small pocket like envelope. Filled it with some basil seeds (what I had available) and stuck everything to a nice flowery paper!
To control this I prepare a saucer with some water and put the paper in when I'm happy with the burnt result. Then I leave the paper to dry. Blowing can cause the paper to burn some more rather than go off.