Lay the whole beef on its side and cut ½ inch thick pieces lengthwise (cut parallel to the grain of the meat). You will get 4-5 slices. Then, take a piece and gently slit the meat in the middle, leaving about ¼ inch before you reach the end. It will look like an open book. Pound using a meat mallet to flatten the meat evenly, being careful not to tear it. Do the same with the rest.
Combine lemon juice, soy sauce and ½ teaspoon ground black pepper in a large food container. Add all the flattened meat, making sure everything is coated with the marinade. Cover and refrigerate for one hour.
Prepare the ingredients for the filling and lay them beside each other in one big plate.
Take the meat out of the fridge. Squeeze one piece (reserve the marinade) to drain the liquid then lay open on a flat surface. Brush the inside with softened butter then place 2 slices of ham beside each other in the middle of the meat. Place strips of carrots, hotdog, pickles and cheese beside each other then add egg halves on top (see photo illustration below). You may have to cut some filling to fit the length of the beef. Roll tightly as you would a jelly roll. Tie a knot on one end then keep turning the twine around the meat roll (about 1 inch apart) until you reach the other end. Fold any loose end and secure with a twine to make sure the filling stays in place. Repeat with the rest. (photos below)
Heat a large frying pan and add ¼ cup oil. Dredge each roll in the flour and add to the hot pan. Sear all sides then set aside.
Heat a large pot and add oil. Saute the onion followed by the garlic. Add the rest of the ingredients for the braising liquid (except the soy sauce). Bring to a boil on medium-high heat. Gently add the seared meat rolls, making sure they’re almost completely covered with the liquid. Lower the heat and simmer for 2 hours***(see notes), checking and turning the rolls every 30 minutes. Taste and add soy sauce , if needed.
Remove the rolls from the sauce. Increase heat and reduce the sauce to the desired amount of liquid.
To serve: Remove the strings then slice (thinly) horizontally. Place some sauce on the serving platter then arrange the sliced morcon on top. Pour more sauce over (if desired) or serve with extra sauce on the side.