1bunch chocolate (or other) mint, leaves only (1 cup medium-packed), washed and dried
4ounceschopped bittersweet chocolate (I used 70% cacao mass)(about 1 cup)
Make the custard base:
Heat 1 cup of half and half in a medium saucepan over a medium flame until warm and steamy, and small bubbles form around the sides of the pot, swirling occasionally.
Pour the heavy cream and remaining 1/2 cup of half and half into a large bowl and place a fine-mesh strainer over the top. Set aside.
In a medium bowl placed on a damp towel for stability, whisk together the yolks, sugar and salt.
Slowly drizzle the warm half and half into the yolk mixture, whisking constantly, then scrape the mixture back into the pot. Cook over low heat, stirring constantly with a heat-proof rubber spatula, until the mixture just begins to 'stick' (form a film on) the bottom of the pot, and/or reaches 170º on an instant-read thermometer.
Immediately pour the custard through the strainer and into the cold dairy. Stir to combine, then chill the mixture in the fridge for at least 4 hours or (preferably) overnight, and up to 4 days.
When you're ready to churn the ice cream, blanch and shock the mint:
Bring a quart of water to a boil in a large saucepan. Have a medium bowl filled with ice water handy, as well as a slotted spoon. Dump the mint leaves into the boiling water, swish to submerge, and count to 10. Turn off the heat, fish out the leaves with the slotted spoon and plunge them into the ice water. (You can use this hot water to melt the chocolate over, as per below, and later, to drink - it is essentially mint tea.)
Pull the blanched mint leaves out of the ice water and squeeze dry. Place the squeezed-dry leaves in a blender. Add about a cup of the chilled ice cream base, and puree on low speed, gradually increasing to the highest speed, eventually pouring in the rest of the ice cream base. The mixture should be fairly smooth, frothy, and mint green in color.
Strain the minty ice cream base through a fine-mesh strainer, and into a large bowl or measuring pitcher,pressing on the mint dregs to extract as much good stuff as possible. Place the mixture in the freezer for 20 - 30 minutes, stirring once or twice, to get the mixture really cold (the blending process generates a bit of heat).
Process the well-chilled ice cream base in an ice cream maker according to the manufacturer's instructions.
Meanwhile, melt the chocolate:
While the ice cream is churning, place the chocolate in a dry, medium-sized metal bowl and set over the pot of hot water from blanching the mint (above). The water should be steaming but not simmering or boiling. Stir the chocolate occasionally until completely melted. (Even a drop of water can cause chocolate to seize or clump up, so make sure the bowl and utensils are bone dry.) Hold the chocolate at a melted but cool temperature.
Place a glass or metal loaf pan or the like in the freezer. (This will help keep the ice cream cold as you layer it with the melted chocolate.)
When the ice cream is done churning, layer it with the melted chocolate:
Working quickly, scribble the bottom and sides of the chilled loaf pan with some melted chocolate, then spread a layer of ice cream over the top. (See photos in post, above.) Scribble more chocolate over the ice cream, and spread with another layer of ice cream. Continue making layers until you've used up all the chocolate and all the ice cream. Cover the pan and freeze the ice cream for at least 2 hours for a scoopable consistency, and up to several months (though good luck with that one).
With burgundy-tipped emerald leaves, chocolate mint conveys all the cool freshness of peppermint with a bit of warmth from earthy cacao undertones. Like all mints, it grows like a weed (or so I'm told), but if, like me, you have less than 2-square-feet of outdoor space, and (unlike me, luckily) lack generous and green-thumbed friends, you may be able to find chocolate mint at a farmer's market. Otherwise, substitute spear or peppermint; both will be delicious.Another soft herb, such as basil in any of its varieties (cinnamon, lemon, thai, or the standard Italian stuff) or lemon verbena, would likely work well, too (though I would omit the chocolate).Nutritional values are based on one of eight servings.