Start with the bigger leaves the ones that feel easier to handle and leave smaller ones for the end to use for covering the bottom of the pot.
Take a large cabbage leaf and lay it flat on your working surface. Remove the harder part from the center. Take about 60 grams / 2.1 oz of the ground meat mixture and shape it into an oval-shaped meatball.
Place it on the bottom end of the leaf and then overlap the end of the leaf over the filling. Tuck in the sides and start to roll it upwards firmly but not too tightly.
NOTE: The first outer leaves may be too big for just one cabbage roll and you will need to cut them in half. For those (half) leaves use about 50 grams / 1.7 oz of filling.
Place the roll in a pan aside. Keep making rolls until you run out of filling.
Then use the leftover leaves and scrapes to cover the bottom of a large cooking pot. I've used one that has a wide 29 cm / 11-inch opening, so it fits a dinner plate inside (which will be used to prevent the rolls from unwrapping while they cook). If you plan on using a narrower cooking pot just make sure you have a plate that fits inside.
Place the cabbage rolls in the pot tightly close to each other with seam side down. You should end up with two layers of cabbage rolls.
Place the plate on top (back side of the plate facing up) to keep them in place. Then pour the vegetable stock into the pot through the side of the plate, and some of the cabbage water you saved. When you press the rolls down with the plate they should sink under the liquid. Otherwise, add a bit more cabbage water or vegetable stock.
Pour in the olive oil as well and place the pot on the heat. Turn the heat to medium and put the lid on the pot, leaving it slightly open on the side. Cook for about 50 minutes to 1 hour from the time it starts to bubble. If your stove is too strong or you are using a gas stove it's better to keep the heat to medium-low so it doesn't boil too strongly.
Turn the heat off. Carefully remove the hot plate from the pot. Tilt the pot to the side and with a ladle start to remove liquid from the pot and add it to a measuring cup. You don't have to remove all the liquid from the pot. About 500-600 ml is enough.