We used a basic salt dough and added brown food colour.
Salt dough recipe
2 cups of plain flour
1/2 cup salt
1/2 - 3/4 cup hot water
+ brown food colour
Just throw everything into a bowl and mix until you get a dough. Then take a small lump of dough, roll it into a ball the squash it flat. We experimented with different tools but found the end of a paintbrush worked best for engraving the numbers.
We baked them at 180∘c for 10 minutes then turned them over and gave them another 5 minutes.
Once they had cooled we painted them with varnish, Ebi-kun is a bit heavy handed with the varnish so some came out a bit splogy.