L.A.
Is there a reason he needs his food mashed up?
Physical reason? Developmental?
If not, quit giving it to him this way. Cut things up into small bites.
place a small spoon and a small fork on the table and leave him alone. If he eats great, if not, that is ok also.
At this age he needs to be feeding himself. even cereal soup, sandwiches. .. etc..
The only help a child this age will usually need, is cutting up their food.