Mix all ingredients in a large bowl. Cover and refrigerate for about 30 minutes so the flavors blend.
Shape into 4-6 patties of desired thickness.
Grill until burger reaches desired doneness--a insta-read therrnometer works well here. As an example, I like my burgers medium and make them about 1-inch thick, so I grill about 8 mins each side.
Notes
Burgers shouldn't be made with extremely lean ground beef, i.e. 90%+. It will be dry because the fat is responsible for the juiciness. The leanest you can go is 85% but experts recommend 80% ground beef for burgers.