01 - Blend the milk and spinach leaves until completely smooth and vibrantly green. Strain through a fine mesh sieve into a medium saucepan to remove any leafy fibers.
02 - Add heavy cream, sugar, and salt to the saucepan with the spinach milk. Heat over medium heat, stirring constantly, until the mixture is steaming but not boiling.
03 - In a separate bowl, whisk the egg yolks until smooth. Slowly pour about 1 cup of the hot cream mixture into the yolks while whisking continuously to prevent cooking the eggs.
04 - Pour the tempered yolk mixture back into the saucepan. Cook over medium-low heat, stirring constantly, until the custard thickens enough to coat the back of a spoon, reaching 170-175°F.
05 - Remove from heat immediately. Stir in peppermint and vanilla extracts. Add green food coloring drop by drop if a more intense color is desired.
06 - Pour the custard through a fine mesh sieve into a clean bowl. Let cool to room temperature, then cover and refrigerate for at least 4 hours or preferably overnight.
07 - Churn the chilled custard in an ice cream maker according to manufacturer instructions. During the final 2 minutes of churning, add the chocolate chips or chopped chocolate.
08 - Transfer the churned ice cream to a freezer-safe container with a tight lid. Freeze for at least 2 hours until firm before serving.