I found that I needed to make a "freezer" type of chocolate to have it yield the best flavor and texture when used in chocolate chip ice cream. I also have discovered that Peggy and I prefer to have some of the sugar in the chocolate chips remain in crystal form as it makes the chips very slightly crunchy. That is a personal preference that is not part of traditional chocolate chip ice cream.
Note that I list a Ghirardelli® 100% cacao bar as the source of the chocolate. I did that because most home chefs will easily find that ingredient at the supermarket. What I use is my 11 pound block of Callebaut® dark block chocolate for baking, which is 70.4% cacao.
Note also that I list food grade liquid soy lecithin as an ingredient for making the chocolate chips. Soy lecithin is an emulsifying agent that will cause the other ingredients to combine well. It is typically used at the rate of one half of one percent of the total weight of the chocolate chips. This means you need to use a precision kitchen scale that can measure accurately to the tenth of a gram. My scale is a reloader scale from Cabela's®. It cost $70 and I use it often for measuring a variety of chemical additives for food, especially preservatives like sodium benzoate. Buy one. You need it.
My source for food grade liquid soy lecithin is www.modernistpantry.com and a 175ml bottle, with shipping, costs under $20. That amount of product will last for a very long time for the home chef.
Have fun making this ice cream and know that it is delicious.
Ingredients: (Makes about 1½ quarts of ice cream)
2 cups of heavy cream
1 cup of milk
2 extra large or jumbo eggs
3/4 cup of sugar plus 1 tbsp. of sugar for the chocolate chip mixture
1 tbsp. of natural vanilla extract
2 oz. of chopped/cut pieces of an 80% to 100% cacao chocolate bar (I suggest using a 4 oz. Ghirardelli® bar)
1.6 oz. of coconut oil
1 oz. of light corn syrup
1 tsp. of water (optional)
0.4 grams of food grade liquid soy lecithin plus one tsp. of light corn syrup
Directions:
Let's talk first about the optional teaspoon of water for the chocolate chips. If you use it and heat the chip mixture to force the sugar to dissolve then the chocolate chips will not have any crystalline sugar evident when you eat the ice cream. If you skip the teaspoon of water or avoid heating the chip mixture to the point of dissolving the sugar completely you will get a bit of sugar crunchiness in the chocolate chips. The decision is yours to make.
Weighing out and using the tiny amount of thick, sticky soy lecithin is a challenge. Use the precision kitchen scale. Put the one tsp. of corn syrup into the weighing pan and put the weighing pan on the scale. Now turn on the power to the scale. It will read zero as the weight. Add the soy lecithin by dipping a paring knife about one inch into the jar of soy lecithin vertically and then lifting the knife out and letting most of the soy lecithin drip/run off the tip of the knife back into the jar. Then hold the knife vertically over the weighing pan and let just enough soy lecithin drip from the knife into the corn syrup, until you have a weight of 0.4 grams showing on the scale display. Remove the weighing pan and gently mix the soy lecithin with the corn syrup. You are now ready for the next step.
Put one tbsp. of sugar, the corn syrup, the water and the corn syrup and soy lecithin mixture into a small bowl. Heat the mixture briefly in the microwave oven for 5 to 10 seconds and optionally mix/stir long enough until the sugar has dissolved and the water and lecithin mixture has mixed completely with the other ingredients. But do stir enough to combine the lecithin.
Use a wooden cutting board to cut half of the 4 oz. high cacao chocolate bar into pieces roughly 1/2" square. Save the other half for a later batch of ice cream. Barely melt the chocolate pieces in a small bowl with the coconut oil in the microwave oven with a 20 second heating cycle on high heat. Stir the mixture to help melt the chocolate, then, if necessary, repeat the heating cycle but only for 10 seconds. Stir until the mixture is well combined, then mix/stir/whisk it together with the corn syrup mixture until well combined. Pour the mixture onto a dinner plate making sure it is evenly distributed and put the plate into the freezer. After the mixture is frozen cut it into irregularly shaped pieces roughly 3/8" square with a large sharp knife and return those pieces to the freezer.
Break the eggs into a five or six quart electric mixer bowl and mix them on medium speed for one minute. Add the 3/4 cup of sugar and the vanilla and mix until well blended, around three minutes.
Add the cream and the milk and mix for two to three minutes on medium speed.
Transfer the mixture to a gelato maker and proceed to make the ice cream. When it is fairly stiff (about twenty-five minutes), add the chopped/cut frozen chocolate pieces and run the gelato maker for an additional three minutes. Transfer the completed ice cream to a one and one half quart storage container. Put the container into the deep freeze for four hours or more to finish hardening the ice cream.
Serve the ice cream and be delighted.