01 - Combine milk, 1 cup cream, sugar, and salt in a medium saucepan. Heat over medium heat until steaming but not boiling.
02 - Remove from heat, add mint leaves, cover, and steep for 1 hour to extract maximum flavor.
03 - Strain out mint leaves, pressing firmly to extract all liquid. Rewarm the mixture if needed before proceeding.
04 - Whisk egg yolks in a bowl. Gradually pour warm milk mixture into yolks while whisking constantly to prevent curdling.
05 - Return mixture to saucepan and cook over medium-low heat, stirring constantly, until thickened and coating the back of a spoon (170–175°F). Do not boil.
06 - Remove from heat and stir in remaining 1 cup cream, vanilla extract, and food coloring if using.
07 - Pour through fine-mesh sieve into clean bowl. Cool to room temperature, then refrigerate covered for at least 4 hours or overnight until thoroughly chilled.
08 - Churn chilled custard in ice cream maker according to manufacturer instructions. Add chopped chocolate or chips when nearly done, churning just until evenly distributed.
09 - Transfer to lidded container and freeze for at least 2 hours until firm.
10 - Let stand at room temperature for 5 minutes before scooping for optimal texture.