We don't eat hamburgers that often, but like one occasionally.
I grind all the meat we use myself, to make sure it's leaner and healthier. Eye of the round, with all visible fat removed, makes for good chili, etc., but makes a hamburger that has the texture of sawdust!
Recently I saw some advice to grind a few pitted prunes in while grinding the beef.
I tried this today:
Ground about a pound or so of lean eye of the round, about 7 prunes, and one medium sweet onion in the KitchenAid grinder attachment. I added a glug of Worcestershire sauce and about a tsp of Kitchen Bouquet. (sometimes i also add some Hidden Valley RAnch powder, too) Formed into 5 patties.
Wow, it was great. So much more moist and you could not detect the flavor of prunes. It had a nice crisp grill-type crunch on the outside and moist on the inside. And I don't think 7 prunes in 5 burgers would cause anyone any, ah..... intestinal disturbances!
On my homemade hamburger buns (with added fiber and whole grains), some fresh tomatoes from the garden, oh wow. Hamburger heaven without the guilt.