Very well, thank you...< rimshot >
Fastest way to mince an onion is to cut into chunks, say 4-6 per onion, then pulse in a food processor until desired size of onion pieces is reached.
I've made these burgers many times, not "meat loafy" at all. The Tabasco and mustard conspire to prevent this sort of side effect... ;^)
I’ve also used an old fashioned foord grater (not as fast, but as effective)....