Homemade Mascarpone - heavy cream

Method

• In a small saucepan over medium heat, heat cream to boiling. Watch the heat - don't let the cream boil over. If you've got an instant read thermometer, you are shooting for a boiling temperature of 190 degrees. On my electric stovetop, the temperature of the boiling cream fluctuates around 180 to 200 degrees F. Continue boiling for 5 minutes, stirring the bubbles down when necessary.
• Stir in the lemon juice and cook, stirring, for about 5 more minutes, or until the cream thickens and resembles a loose bechamel sauce. Remove saucepan from heat and let cool, about 15 minutes. The cream will thicken more.
• Fit a medium-sized mesh sieve over a medium bowl. Place a large cheesecloth square over sieve. Pour thickened cream over cheesecloth-lined sieve. Fold the ends of the cheesecloth over. Cover the bowl with plastic wrap. Refrigerate in the sieve for at least 12 hours, or overnight. I prefer a firmer mascarpone, so I like to lay a small dish or two (like a demitasse saucer) over the top to weight it down slightly.
• Turn mascarpone out into a bowl, cover and refrigerate until ready to use. Mascarpone usually keeps for about 5 to 7 days.
• If you can keep yourself from eating the whole thing right then and there, the mascarpone is outstanding with radishes, as in this recipe: http://www.food52.com/recipes/8049_radish_mascarpone_honey_salt