1. Prepare the custard base as directed in the recipe (including chill time in the refrigerator).
2. Remove custard from the refrigerator and stir with a rubber spatula. Transfer the mixture to a freezer-safe bowl or container (if not already in one). Cover tightly with plastic wrap or an airtight cover. Place in the freezer and allow to freeze for 2 hours.
3. Remove from the freezer and beat with a hand mixer to break up the ice crystals that are beginning to form. Cover and place back in freezer for 2 more hours.
4. Remove from the freezer and beat again with the hand mixer. The ice cream should be thick but too soft to scoop. If it is not thick enough, return it to the freezer for additional freezing time. Beat again. If the ice cream has thickened properly, stir in any add-ins at this point (chocolate chips, cookie chunks, etc.). Do not beat with the hand mixer after the add-ins have been mixed in.
5. Pour into a plastic airtight freezer container, leaving at least ½-inch space at the top. Cover and place the container in the freezer and allow the ice cream to freeze until firm.
