Tin can base
A base for placing a tincan upside down onto it, the inset "lip" makes easy centering and for a larger glueing area.
It's a bit of an overengineered solution for the problem at hand, but when you're a hammer everything looks like a nail :)
Paints used in the example:
Maston One Primer White
DecoArt Americana True Ochre
DecoArt Americana Raw Umber (sparingly dabbed on using a scouring pad)
DecoArt Media Ultra Matte Varnish