Mr. and Mrs. Miscellaneous Basil-Chip Ice Cream

Set a large metal bowl inside another large bowl filled with ice water. Lightly beat egg yolks in a medium bowl. Bring cream, whole milk, and sugar to a simmer in a medium saucepan. Whisking constantly, gradually stream half of cream mixture into yolks. Return egg mixture to saucepan and cook over medium-high heat, stirring constantly with a wooden spoon, until mixture coats spoon, 2 –3 minutes. Strain through a fine-mesh sieve into prepared bowl. Stir in condensed milk and salt. Let cool, stirring occasionally, 20 –30 minutes, then stir in buttermilk. Using an immersion blender, mix base until smooth and silky. Add basil; mix until finely chopped. Cover and chill 2 days. Blend base with immersion blender; strain into an ice cream maker. Process according to manufacturer's directions. Meanwhile, grate chocolate on the large holes of a box grater into a large bowl. Add ice cream and fold to evenly incorporate chocolate. Transfer to an airtight container. Cover and freeze at least 2 hours before scooping.