• 8 prime rib slices, carved thinly
• 4 sandwich rolls - ciabatta or sourdough, split lengthwise and lightly toasted (optional)
• caramelized onions
• creamy horseradish sauce
• dijon mustard
• lettuce or arugula
  

Slice rolls in half, leaving the top bun attached at one end.

Spread horseradish and dijon mustard generously on each side of the rolls and layer with prime rib slices, caramelized onions and lettuce. 

Season with salt and pepper.