I like bwarbiany's idea on the heat treatment.. If you're not doing this sous vide, I get the color as soon as possible, and then back off to cook through. As with Turkey burgers, need to add some fat. sour cream or mayo are good for this, along with olive oil. another nice cheat is to add a liquid (soy, buffalo, or minced onion or chives to get a little bit moisture. I will be heavy on my burger rub. I tend not to use bread crumbs or eggs, as well, I'm sorry, then you're making a meatball.