Preheat oven to 425 degrees. Line a cookie sheet with a slipat mat or parchment paper.
In a skillet over medium high heat, melt your butter. Add thinly sliced onions to your butter. Stirring them until they are caramelized. About 8 minutes or so. The onions will be browned and fragrant.
Add kraut to onions and cook for a couple of minutes more. Remove from pan.
Add your steak, thinly cut into thin strips, to your skillet. Salt and pepper and cook until done. About 5 minutes. Remove from pan.
In a small bowl, mix up cream cheese, mayo, horseradish sauce and chives.
Roll your pizza dough out into a rectangle shape. I rolled mine onto a cutting board.
Spread cream cheese mixture over dough, stopping just shy of the edges.
Sprinkle with prepared steak, onions and kraut.
Sprinkle with cheese.
Roll the dough from the long side, taking care to stretch the edges to seal.
Cut into slices, about 3/4" thick.
Place on cookie sheet, bake for about 17 minutes, or until brown.
Serve hot.