About two or three strips of good bacon on a pure elk pattie sure makes it hard to beat.
And that's the right time to add it, too. We ground some fat bacon in with some elk burger one year, and I didn't like the fact that all my wonderful elk burger tasted like bacon. YMMV, but I'll not do that again.
Now we use some fat pork meat and everyone's happy...even though we don't use enough to make much difference in the taste of the finished product.
