A double butterfly-cut roast, such as a pork or beef loin, stuffed and rolled into pinwheels may fool dinner guests into thinking you're secretly a master chef. This butterfly technique turns a rectangular or cylindrical piece of meat into a flat rectangle. You can spread filling such as cornbread dressing or rice and vegetables over the rectangle, roll it up as you would roll a carpet, and tie it with butcher's string. This is an alternative cutting method to spiral cutting a roast and is much easier to make the roast uniform.
Trim excess fat from the roast with a boning knife. Fat helps flavor the meat, so don't cut off all the fat.
Set the roast on a cutting board with one end pointing toward you. Hold a long chef's knife parallel with the cutting board, positioned about 1/3 of the way down from the top of the roast. Slice through the roast horizontally along the long side, stopping about 1 inch before you reach the other long side.
Flip the roast over so the uncut long side is on the same side as your dominant, cutting hand. Measure1/3 down from the top of the roast; this was the bottom of the roast before you flipped it. Make a second horizontal cut through the roast, stopping 1 inch before you reach the other side.
Pull back the cut flaps of meat, opening each like a book. Each flap opens in opposite directions so the roast is flat on the work surface. In the folded position, you might think of the roast as a folded letter in which the top 1/3 of the paper is folded over and the bottom 1/3 is folded underneath.
Pound the roast with a meat mallet, as needed, to ensure it lies flat with even thickness throughout.