Place the whipping cream in a large saucepan and stir over low heat for about 3 minutes, or until reaches 185°F (85°C).
Add in the lemon juice, and continue to stir over low heat for 2-3 minutes, then remove the pan from the heat and allow the cream cool.
Place a sieve lined with a tea towel or 3-4 layers of cheesecloth over a bowl. Pour the cream through the sieve, only few drops of the cream should be able to reach the base of the bowl, if it's more, use 2 layers of tea towel to prevent it.
Cover the cream and place in the refrigerator for 24 hours. The mascarpone cheese is ready when it reaches a rich and creamy texture.
How to Store Your Mascarpone Cream Cheese
You should store homemade mascarpone in an airtight container, in the fridge, and it will last up to 3-4 days. I don't recommend freezing it.