I was getting a small loin roast ready to make a Smoked Stuffed Horseradish Crusted Pork Roast so I thought I'd post how the roast is roll cut.
Roll cutting a pork loin:
With the end of the roast facing you, cut a lengthwise slit 1/2-inch from bottom to within 1/2-inch of the edge on the other side of the loin. Open the flap you have just made. Make another cut through the thick portion of the pork loin, again 1/2-inch from the bottom and to 1/2-inch from the edge. Unroll the loin to form a flat piece of meat. Repeat until pork is an even 1/2-inch thickness. Pound the meat, if needed, to make it an even thickness.
1 1/2-pound boneless pork loin
After making the first cut
After making the second cut
If necessary you could keep repeating the cuts until the roast gets to an even thickness. You want each section to be about 1/2-inch thick.