If you would like a darker green ice cream you can add green food coloring to the custard, when you add the mint extract and whipping cream, before placing the mixture in your ice cream maker. Add as much coloring as you need for the desired color.

You can also add green swirls with food coloring. After the soft ice cream has been poured into a freezer container, take about a cup of ice cream out of the container and put it in a bowl. Color this separate batch to the desired green. Pour the greener ice cream back into the ice cream in the freezer container and swirl it through the container, making sure to get it down to the bottom as well.