01 - Combine the heavy cream, whole milk, and half of the sugar (3 tablespoons) in a medium saucepan. Heat over medium heat, stirring occasionally, until the mixture reaches a steaming point but does not boil. Small bubbles should form around the edges.
02 - While the dairy mixture heats, place the egg yolks in a heatproof bowl. Add the remaining sugar and whisk vigorously until the yolks become pale yellow and slightly thickened, about 2-3 minutes.
03 - Slowly pour about 1 cup of the hot cream mixture into the egg yolks while whisking constantly. This gradual process prevents the eggs from scrambling. Continue whisking until fully combined.
04 - Pour the tempered egg mixture back into the saucepan with the remaining cream. Cook over low heat, stirring continuously with a heatproof spatula or wooden spoon, until the custard thickens enough to coat the back of the spoon (reaches approximately 170°F). This takes 5-7 minutes. Do not let the mixture boil.
05 - Remove the saucepan from heat immediately. Stir in the peppermint extract, vanilla extract, and sea salt until fully incorporated.
06 - For natural coloring, blend the warm custard with fresh spinach leaves in a blender until completely smooth, then strain. Alternatively, stir in green food coloring a few drops at a time until you achieve the desired vibrant green shade.
07 - Pour the custard through a fine-mesh sieve into a clean bowl to remove any cooked egg bits. Let cool to room temperature, about 30 minutes. Cover with plastic wrap pressed directly onto the surface to prevent skin formation. Refrigerate for at least 4 hours or overnight until completely cold.
08 - Pour the chilled custard into your 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 dark chocolate.
09 - Transfer the churned ice cream to a freezer-safe container, pressing a piece of parchment paper against the surface. Cover tightly and freeze for at least 4 hours or until firm enough to scoop.