In a medium saucepan, stirring now and then, slowly bring the cream up to 180 degrees F. and hold it for three minutes, at the 180 mark or as close as you can get. Add in the lemon juice (and salt, if using) and continue to hold at 180 degrees F, stirring now and then for about three minutes. The mixture should coat the back of a spoon.

Remove from heat and let cool for about 30 minutes or until room temperature.

Set up a small strainer over a larger bowl. Line with cloth, several layers of cheesecloth or a coffee filter. Pour mixture into strainer. Place into the fridge, lightly covered and leave overnight (or approximately that amount of time) until cheese has reached desired consistency. If needed, give the cheese a turn so the center drains properly and return to fridge.

Do not discard any liquid in the bowl yet. You will likely find the cheese in the strainer to be a bit thicker and denser around the edges and more liquidy in the center. Gently blend together. If the mascarpone is still too thin, turn it over in the cheesecloth and drain a bit more. If too thick, add a little bit of the liquid back in.

Store in the fridge, tightly covered and use in 1 to 3 days.

Note: larger batches work just as well, but youll find that they strain a little more unevenly. You may wish to divide the mixture among smaller strainers or, in the morning, give the mixture a turn and leave it to strain longer to the desired consistency.