Scoff has long been an English slang term meaning to gobble down one's food. In the late 1950s those crazy Americans modified this, apparently without cause, to 'scarf'.
In current usage scarf is most often used in the phrases 'scarf down' and 'scarf up', both meaning to eat quickly, hungrily, and/or greedily. The phrase 'scarf up' has been generalized to also mean 'grab greedily', although this is less common. And finally, 'scarf out' is sometimes used to mean 'overeat'.
The average American will probably no longer recognize 'scoff' as a term related to food in any way, and will scoff at your malapropism if you use it in that sense.
Brevity Quest 2016