The following instructions are for making a classic vanilla bean ice cream. With minimal variations, all revolving around the additions of fruit, chocolate or other flavorings, the same procedures will apply to many custard-based recipes as well as to the denser, generally richer Italian ice cream known as gelato.
Whichever recipe you use, pay careful attention to including the precise measurements indicated for each ingredient. Any changes you make in the amount of sugar or any addition of extra ingredients that contain alcohol could adversely affect the frozen consistency of the ice cream. Bear in mind that the mixture will taste sweeter before freezing than after. Take care, as well, to follow instructions for whatever type of ice cream maker you use. Unless you prefer the consistency of soft-serve ice cream, allow sufficient time for the finished product to harden in your freezer.
1 vanilla bean
3 cups half-and-half
3/4 cup sugar
6 egg yolks
1. Scraping the vanilla bean.
Use a small, sharp knife to cut the vanilla bean in half lengthwise. With the tip of the knife, scrape out and reserve the small, dark seeds clustered inside the bean halves.
2. Heating the half-and-half.
Pour the half-and-half into a saucepan. Add the vanilla seeds and bean halves to the pan and bring to a simmer, heating it just until bubbles appear at the pan's edge. Remove from the heat, cover and let steep for 30 minutes, then return to a simmer.
3. Steadying the bowl.
In a metal bowl, whisk together the sugar and egg yolks. Form a kitchen towel into a ring on a work surface. Place the bowl in the center of the ring to prevent it from moving while you whisk the ingredients. Whisking continuously, gradually add the hot half-and-half mixture to the egg yolk mixture to form a custard.
4. Cooking the custard.
Return the mixture to the same saucepan. Place over medium-low heat and cook, stirring with a wooden spatula or spoon, until the custard thickens sufficiently to leave a path when you draw your finger across the back of the spatula, about 5 minutes. Do not allow the custard to boil.
5. Straining the custard.
Set a medium-mesh sieve over a clean bowl. Pour the custard through the sieve to remove the vanilla pods and eliminate any lumps. Then refrigerate the custard until cold, about 1 hour.
6. Freezing the ice cream.
Transfer the cold custard to an ice cream maker and process according to the manufacturer's instructions. Transfer the ice cream to a chilled freezer container, cover and place in the freezer until firm, 3 to 4 hours. Serve with an ice cream scoop, dipping the utensil into a bowl of hot water, if necessary, to aid in scooping.