01 - Combine heavy cream, milk, and half of the sugar in a medium saucepan. Heat over medium heat, stirring occasionally, until the mixture reaches a steaming point but does not boil.
02 - In a separate mixing bowl, whisk the egg yolks with the remaining sugar until the mixture becomes pale yellow and slightly thickened, about 2-3 minutes.
03 - Slowly pour about one cup of the hot cream mixture into the egg yolks while whisking constantly. This gradual process prevents the eggs from curdling. Pour the tempered mixture back into the saucepan.
04 - Cook over low heat, stirring continuously with a heat-proof spatula or wooden spoon, until the custard thickens enough to coat the back of the spoon. The temperature should reach approximately 170°F. Do not let the mixture boil.
05 - Remove from heat immediately. Stir in the peppermint extract, vanilla extract, and sea salt until fully incorporated.
06 - For natural coloring, blend the custard with fresh spinach leaves in a blender until completely smooth, or stir in food coloring until the desired vibrant green shade is achieved.
07 - Pour the custard through a fine-mesh sieve into a clean bowl to remove any bits of cooked egg or spinach. Let cool to room temperature, then cover with plastic wrap and refrigerate for at least 4 hours or overnight until completely chilled.
08 - Pour the chilled custard into an ice cream maker and churn according to the manufacturer's instructions, typically 20-25 minutes. During the last 2 minutes of churning, add the chocolate chips or chopped chocolate.
09 - Transfer the churned ice cream to a freezer-safe container, pressing a piece of parchment paper against the surface to prevent ice crystals. Cover tightly and freeze for at least 4 hours or until firm enough to scoop.