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The video for the song "Radioactive" by Marina and the Diamonds fits a lot of your criteria there. She matches the physical description pretty well (although she isn't blonde but she wears a blonde wig in the video) and she is known for her retro style. There are people wearing masks in the video and there is a scene where they trash a diner. However, there is nothing in it about hamburgers. She does sing a line ending in "woah" and it's possible you misheard the lyrics. It was released in 2012 and wasn't a huge hit but she does have a big fanbase, so you might have come across it somewhere. Give it a try: https://www.youtube.com/watch?v=dU7GoCKSQfg
Other than that, the only song I found that was remotely close was a surreal video by an indie pop band called Best Coast. The song's name is "When I'm With You". It doesn't fit your criteria that well but it does have a blonde singer in a retro-looking outfit and there is stuff about burgers in it. Nothing else fits though so it's probably a long shot. Maybe try other songs by that band and see if any fit because it seems that 1950s is the aesthetic they go for. https://www.youtube.com/watch?v=nN1XzxOQWrA&feature=youtu.be
Bumping to make sure you see this and because I am genuinely curious if I got it right
...and bumping again in case anyone else has any ideas.
Maybe something by Southern Culture On The Skids?
The song was placed in a diner where the singer was cooking hamburgers. While cooking, men in animal masks and suits come in and attack her. She hits one with a frying pan, and escapes. In her music videos, these guys in masks were always in them. The singer was blonde, mid 20s (i assume) and pretty curvy. She had curly blonde hair, wore red lipstick and had a pseudo- rockabilly/1950s look. She wore leather jackets and polka dots a lot. The genre was pop/rock-ish, but wasn't mainstream because I only heard of her a couple times. I can only remember one line of lyrics: "A pretty patty, a pretty patty woah". I think it was released in 2010-2012 but no later than that. I've been looking for this since 2013, so any help would be nice.