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Thankfully, they soon browned and lost the purpleish hue and once blanketed with sharp cheddar cheese, looked pretty normal:
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And when presented on a bun with all the fixings, it would take a very sharp eye to spot anything amiss:
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In case you are crediting me for unexpected creativity, I have to tell you I read about blueberry burgers at a fun blog called ACME Instant Food (updated: sadly the site appears to have been taken down but there are plenty of other recipes on the web; just google berry and burger and you get a ton!)
Here's my version:
Blueberry Burgers
1.25 lbs lean, grass-fed ground beef
1/2 C frozen blueberries, thawed and chopped fine, either with a knife or in a food processor.
1/2 t kosher salt
1/2 t fresh ground pepper
1/4 t garlic powder
Squish all ingredients together to incorporate the blueberry mush into the meaty mush. Don't get carried away and over squish it--just enough to get the job done. Shape into patties and cook on a grill, grill pan, or frying pan.
Top with whatever you like--cheese, mushrooms, onions, condiments...
Serve with LOTS of napkins.