Slice the lemons into wheels, thin as you can, and toss them into the pan. Add your sugar and water and turn the heat on to medium high. Melt the sugar into the fruit and then turn the heat down to low and simmer. You’ll be simmering for a while, maybe 45 minutes to an hour or so. The liquid will thicken and the fruit will soften. Keep cooking, stirring occasionally to keep the bottom from burning, until it makes a thick syrup. Put your jam into a sterilized jar and put the lid on it and let it cool. Store it in the fridge!