I always thought that the only correct is make lunch or cook lunch. But in this video at 30 minutes and 32 seconds a native English teacher is saying that it is possible to say
I am going to make a lunch
I am going to make lunches.
He doesn't explain the difference though. What is the difference? For that matter, can I say
I am making a breakfast?
If so, then what would be the difference between make breakfast and make a breakfast?