Let me state categorically - there is no cat food in cat food pie.
This is one of my own recipes. I cook up a whole load of yummy vegetables and some meat and put it in a pie dish lined with pastry. Sounds easy so far, but what I have not said is that I divide the pie up by putting all the yummy mixture up one end, and at the other end goes all the things that the little ones will eat without picking through the meal at the table and removing the bits they don't like one by one with a running narrative of how they don't like those bits.
Sometimes their end of the pie gets a bit complicated and looks like a map of some country divided up into small regions like "The Land of No Tomato" and "The PFZ" (Pea Free Zone) and "Cheezonlyonia"
To be able to recognise the tasty bit for me and the plain and boring bit for them I make a pastry face on the pie. This is crucial as the little ones will tell you it is more important how food looks than what it tastes like. At least they'll say that first, and then they proceed to tell you that it doesn't taste nice bit by bit.
I love the pie. I think it tastes great. But it is at this point that it gets its name.
"Yuck!" says The Small One "It tastes like cat food."