Since I just posted the recipe for Guiness Ice Cream, I thought it would be a good time to discuss how to make a basic Creme Anglaise, which is the fancy term for French ice cream base. Below is the recipe. It makes a basic vanilla ice cream, but you can take this and add any flavor or combination of flavors (think Ben and Jerry's!) that you wish. The sky's the limit!
8 oz milk
8 oz heavy cream
4 oz egg yolks (6 large yolks)
4-5 oz sugar
1/2 vanilla bean (or 2 tsp. of vanilla extract—I love Nielsen Massey's Vanilla Bean Paste)
pinch of salt
Scrape the seeds from the vanilla bean into the pan and add the vanilla bean halves. If you are using a flavoring that needs to infuse (green tea for example, or whole cinnamon), add it now.
You want to scald the milk, not boil it. This means you want to heat it on medium until the edges begin to bubble. You want to keep an eye on it because it will boil over the edges of the pot if it gets too hot. If the flavoring you are using needs a longer infusing time, cover the pot and let it sit for an hour. Remember to taste! Bring back to a simmer, then remove from heat.
Beat the egg yolks and sugar and just a pinch of salt in a medium-sized bowl. Salt seems an odd addition, and it isn't included in a lot of ice cream recipes. But salt is a flavor enhancer, and adding just a pinch adds depth, not saltiness.
Temper the yolks by slowly drizzling 1 cup of the hot cream into the yolks while constantly whisking the mixture. A liquid measuring cup or ladle is great for this. The tempering process allows you to add a hot liquid to egg yolks without causing them to cook quickly and form bits. If you add the liquid a little at a time, it brings the temperature up slowly and creates a smooth mixture.
Gradually add this mixture in a slow steady stream to the remaining hot cream. Cook over medium-low heat, stirring constantly, until nappe, or when the mixture thickens enough to coat the back of a spoon (170F on an instant-read thermometer), about 5 minutes. I find that a wooden spoon is the easiest to test for thickness on. You'll also be able to feel the mixture thickening as you stir, and it will begin to look glossy. Do not boil!
Remove from heat and strain through a fine mesh strainer into a clean container. If you are using a fresh vanilla bean, wash it off and save it in a plastic baggie. They can be used a couple of times over. Or, you can put it into a container of sugar to flavor the sugar with vanilla. It's great in coffee!
If you are adding liquid flavorings (such as a liqueur, or an extract) you can add them now or after the mixture chills. Adding them at this point allows the flavors to mature while the mixture chills, but the flavor is harder to gauge when the mixture is warm. Flavors are muted when food is cold (although you can add some now and add a little more later if you need to). Also, remember that too much alcohol can interfere with the mixture's ability to freeze.
Cover with plastic, pressing the wrap down so that it rests on the surface of the mixture. This keeps a skin from forming. Chill in the refrigerator for at least 2 hours or overnight.
Remove mixture from the refrigerator. Whisking to blend flavors even if you added them before chilling to eliminate any separation. Pour into the bowl of an ice cream machine and freeze according to the manufacturer's instructions. If you want to add in fruit or other flavorings (like cookie dough—yum!) do it now. If needed, transfer the mixture to a bowl so that you can distribute the flavoring evenly.
Transfer to an airtight container and freeze until firm and ready to serve.