Eating can transform food into energy, and eating in dreams also has the significance of gaining psychological energy.
The ashes were left by the deceased. Eating ashes means you want strength from the dead. Did the elders in the family die? Maybe I hope they can bless you. Or what did you learn from their death, and your body and mind became more mature; Or you just understand now that someone alive actually helps you a lot and has a great influence on you.
Eating ashes can also mean sharing inheritance.
Also, if you have heard Degang Guo's joke about drug squad members eating ashes, this dream may have another meaning.