Jamie: this is one behaviour that I would've corrected as soon as possible. It's so much easier on a 7-week-old puppy than it is on an adolescent or adult dog
Since your dog is still a puppy, I would still try to correct him for this. Don't mess with his food once you put it down, but don't tolerate any aggression from him either.
I don't believe in correcting aggression or dominance issues with bribes and treats... instead of trying to distract him by adding treats into his bowl, I would correct him instead.
You said that correcting him didn't work. Well, it does work if you correct hard enough (malamutes can usually take A LOT).
It's really too bad you didn't fix this when he was a baby though, it would've been 100 times easier
... all it took for my male shepherd (at 7 weeks) was for me to grab his scruff and give a quick jerk on it with a firm NO!
I never took his food away or touched it, but I made sure he got used to me petting him while he ate. I corrected each time he growled but then let him get right back to eating and would praise him again.
It only took two sessions of this to make his food guarding disappear - he's 13 months now and I can stick my hand into his mouth while he's eating and he could care less
Get a prong collar, make sure it's fitted very snug high on his neck and put a leash (or a tab leash) on him before you feed him. When he growls at you, give a HARD JERK on the leash as you say NO!! Don't give in here... if he bites you or continues growling, your correction was too weak.
Make the correction as swift as you can and let him get back to eating right away - don't nag him about it.
Wait a few seconds and try petting him again - if he growls again, give him a much harder correction (again, as you say NO).
He should give a little yelp and immediately knock off with the aggression.
I hope you can fix this now - every time you back off when he growls and bites you, you're just showing him that he's dominant over you.
Frankly, if this were an adult dog with serious guarding issues I don't think it would be a fight worth fighting. If this dog were 2 or 3 years old, I would tell you to just feed him in his crate because it's too late to try and fix it at that age.
At 6 months you should be able to get this under control... just stop giving in to him. Good luck, and be careful not to get bitten
PS: while I don't believe in jerking a dog around to train it, I DO believe that you must absolutely give a VERY hard and memorable correction for ANY sign of handler aggression. This is beyond unacceptable behaviour and you shouldn't be afraid of hurting his feelings... at 6 months he's not a real threat to you so you can still win. You'll be happy you got this fixed before he reaches maturity - at that point it will most likely be a fight that you can no longer win.
Good luck.