Supermarket beef burgers. They are not beef burgers in the same sense that they are in the US or the UK; not meat plus filler but pure meat. They are referred to as steak hache rather than beef burgers and are well worth frying up on your barbecue.
They can get even better. Whilst in Burgundy we found that it is quite easy to get steak hache made from properly serious breeds of beef, Charolais specifically. These were super meaty and totally tasty. This is what burgers are all about, and they are all waiting for you in those hypermarkets over the channel.