To prepare your matambre, you’ll need to start by butterflying a flank steak—this technique is also used in my chivito steak sandwich recipe. Here’s how: Lay the meat flat on your cutting surface. Holding your knife parallel to the countertop, cut through the steak, almost to the opposite end. When you’re done, you will be able to unfold the steak so it looks like an opened book.

Next, cover the meat with a piece of plastic wrap. Using a flat meat pounder, gently pound the steak until the whole thing is about ¼ inch thick. It's essential to opt for a flat meat pounder rather than one with teeth to prevent tearing the meat and achieve an even surface.

Because this is a stuffed steak recipe, you’ll need to wrap the meat in cooking twine after stuffing it and rolling it up. Have five pieces of twine ready before you start assembling your steaks. After you add the filling, carefully roll up the meat over the filling, jelly-roll style, starting at one of the shorter ends of the meat.

Try to keep the meat roll as secure as possible, so all of the ingredients stay inside! Wrap the twine around the meat and tie the ends to secure it in place before popping it on the grill. You can use a toothpick to hold the roll together while you tie the twine if you need to. I explain the whole technique in the recipe below—and you’ll learn how to grill it to perfection. Bonus: In case you don’t want to fire up the grill, I’ve included oven directions as well.