Set our your equipment and ingredients so that you can focus on the cheese making. The equipment you’ll need is: a non-reactive heavy 2-quart saucepan, a kitchen thermometer; whisk; metal spoon, spatula, and a couple of paper towels.
Whisk together the heavy cream and powdered non-fat milk until they’re fairly well mixed. There will be some small lumps left. Place the pot over low heat and slowly bring the cream mixture up to 180°F, stirring constantly to prevent scorching. This will take about 40 minutes. Turn off the heat.
Squeeze the juice from half of the lemon into the cream. Switch to a metal spoon and keep stirring. Using a whisk at this stage will inhibit curd formation. You will not see the clean break of curds and whey that you normally see in making farmer’s cheese or ricotta cheese. It’s a very subtle coagulation that shows up as a thickening of the mixture. As you stir with the metal spoon and remove it, the cream will coat the spoon. You might see some very small flecks of solids in the cream. This takes about 5 minutes.
Add the juice of the remaining lemon half and continue to stir, to incorporate it into the cream. Stir for another 2 – 3 minutes, cover, and place in the refrigerator overnight. Keep the lemon halves for zesting into the finished cheese.
The next morning, remove the mascarpone from the refrigerator. It should be firmed up. Using a spatula, place the mascarpone onto a paper towel.
Draw the corners and sides together to form into a ball, and gently squeeze out the excess moisture. This makes the cheese thicker. See Recipe Notes for more details.
Zest the lemon halves and fold into the cheese along with a pinch of salt. The cheese is now ready to enjoy! It's great on its own, paired with fresh strawberries, or smeared on dried fruit pieces or fruit gelèe. Dried figs and apricots are wonderful choices. Or, obviously you can use it in baked goods that call for mascarpone or cream cheese.