Cook whipping cream
Pour heavy whipping cream into a saucepan. Set over medium high heat and cook until cream reaches 80°C – 85°C (175°F – 185°F). Lower the heat and add the lemon juice. Cook for another 5 minutes, then remove from the heat and allow to cool for 10 - 15 minutes.
Line a fine-mesh strainer or sieve with a cheese cloth (or double kitchen towel). Suspend over a bowl and pour in the cream. Once the cream cools to room temperature, move the sieve and the bowl to the fridge overnight.
Store or use
The next day, squeeze the remaining liqud from the cloth and store the finished mascarpone in a covered dish, then refrigerate. It can be stored for up to a week in a fridge.