• Salt and pepper the tenderloin.
• Cook tenderloin via, sous vide, oven or grilling methods. 

  Sous Vide Cooking: Fill a pot or sous vide container with water and attach the immersion circulator. Set the temperature for 130-135 for medium rare, 135-140 degrees for medium, and 145-155 for medium well. Once water is up to desired temperature, add the prepared tenderloin to the bag and squeeze the air out of the bag. Slowly lower the bag into the water allowing any air to escape, then zip the bag. Cook for 2-3 hours at desired temperature. Once desire temperature is reached, remove the tenderloin from the bag, pat dry with a paper towel and lightly salt. Place on a hot grill for 30-45 seconds per side to get a nice char. 

  Oven Cooking: Place prepared tenderloin in a roasting pan. Cook tenderloin in a preheated oven set to 200 degrees for about an hour or until a thermometer inserted in the middle reaches the desired internal temperature. 

  Grill Cooking: Cook over indirect heat for 45-60 minutes, or again, until it reaches the desired internal temperature. 
• Once tenderloin is done, let rest for 10 minutes before carving. 
• While the tenderloin is cooking slice the onions. Add oil to a sauté pan. Over medium heat, cook onions until caramelized, stirring occasionally for about 30 minutes. Set aside.

Horseradish Sauce

• Mix together sour cream, horseradish, dijon mustard, lemon juice and salt. Set aside.

Building the slider

• Toast buns in the oven.
• Add horseradish sauce to the bottom of the bun.
• Add caramelized onions, tenderloin slices, arugula and blue cheese crumbles.
• Serve and enjoy!