Place the black sesame seeds into a clean spice grinder. Pulse intermittently until a powder consistency is attained. Be sure not to overgrind or it will turn into a paste.
Make the black sesame soup:
In a saucepan, add in the water, rice flour, glutinous rice flour and black sesame powder. Bring to a simmer over low heat. Stir continuously. The mixture will start to thicken.
Continue to stir for about 10 minutes and add in the honey/sugar. Stir until dissolved. Taste the black sesame soup and adjust for sweetness. If the black sesame soup is too thick for your liking, add in a little more water and stir until homogeneous.
Remove from heat and ladle into small bowls. Serve warm.