In a large bowl, using a handheld mixer, beat the egg yolks with 3/4 cup of the sugar at medium-high speed until fluffy, 3 minutes. In a saucepan, combine the milk with the remaining 2 tablespoons of the sugar and bring to a simmer. Slowly beat the warm milk into the egg yolks at low speed. Scrape the custard into the saucepan. Cook over moderate heat, stirring constantly with a wooden spoon, until thick enough to coat the back of the spoon, about 5 minutes; don't let the custard boil.

Pour the custard into a bowl and whisk in the mascarpone, lemon juice and salt. Place in refrigerator for 2 hours or until well chilled.

Pour the custard into an ice cream maker and freeze according to the manufacturer's instructions. Transfer the mascarpone ice cream to an airtight container and freeze until firm, at least 2 hours.