Mix wet and dry ingredients until all incorporated into beef mixture. 
If the wet and dry ratio won't allow for the patties to form, add more shiitake powder to thicken the burger.				
Mix your dry ingredients until well seasoned. 	
Divide your ingredients into 3 separate containers. 			
1-Thin Sliced whole onion rings					
2-Dry Seasoned Flour Mixture					
3- Buttermilk 					
Dip your sliced onions into the flour mixture. 
Knock off any excess flour, then soak into the butter milk for 10 minutes. 
Once your onions have soaked, take your onions and place into the dry mixture.
Toss to completely coat.					
Once they have been covered with your seasoned flour, slowly float the coated onions in the fryer at 350 degrees.
Allow to brown, and slowly stir so they don't clump.
Once you remove from the fryer, season quickly while they are still hot and moist from the fryer liquid. 
Reserve for the sandwich.