Minced Bacon and render until crispy, allow to cool. 
In a large bowl, mix beef, eggs, tomato juice, A.1. and seasoning salt. 
Add cooled bacon and fold together. 
Form into 8 oz. burgers, liberally season both sides with season salt. 
In a skillet, sauté onions in butter and deglaze with bourbon.
Slice mushrooms and add to onion bourbon mixture.
Continue to sauté until tender. 
Begin to grill burger on medium heat, until desired temperature is reached.
Top with mushrooms and onions, recheck seasoning and preseason if needed.
Top with horseradish cheese and melt.
Toast bun, and smear with horseradish mayo mixture. 
Add burger, mushroom, onion and cheese to bottom bun, then top.