Tried to make some burgers the other day. Mixed minced beef, onions, herbs and egg, then shaped them and when tried to cook they crumbled all over the place. I was quite surprised considering that the ones from the supermarket don't crumble at all. I thought that it was probably due to the fact that the meat I minced had no fat at all but am not so sure. Anyone have a decent recipe which has been tried and tested please?