Done can mean done
When they say they are done, believe the first clear signal. Chasing them with a spoon stretches the meal into a fight.

Believe the first clear done
Food can come back at the next snack. It does not have to come back as a negotiation.
“All done,” a turned head, an empty interest. Pick one signal you will trust, and trust it tonight.
The spoon chase
One more bite, then one more, is how a short meal becomes a scene. Stop at done.
If you are worried they did not eat enough today, look at the whole day, and talk to your child’s doctor if growth is the worry. Do not collect the missing bites by force.
A calm ending
Clear the plate. Wipe hands. Move on. The ending teaches them that done is a real word.
The familiar food can be the first thing offered at the next snack, so done was not a door closing on food.
A sentence you can say
“You’re done.”