As far as using the ice cube trays, you can freeze water in the tray.  Pop
out 2, 3, 4 ice cubes, however many spaces you need.  Fill these empty ones
with EBM.  When they are frozen, pop them out, and store in separate
container and date it.  And start the process again. This worked for me and
I never wanted to add fresh EBM  to already frozen ebm cubes.
Sometimes it still is too much of a bother.  It works a bit easier  for
making/storing your own baby food.

Teri Shilling in Gunnison, CO where it gets cold enough to instantly freeze
ebm in the winter.