Fill a large bowl half way with ice. Pour cold water over the ice so that the bowl is no more than ⅔ high. Place a clean bowl on top of the water bath. Place a strainer over the empty bowl. Set aside
Scrape the vanilla bean and add it to half the sugar (you can eyeball half) in a 2 or 3 quart saucepan. Add the vanilla bean paste, the milk and the cream and whisk over low to medium heat, stirring occasionally to ensure the sugar dissolves. Heat to a simmer.
While the liquid heats up, vigorously whisk the egg yolks with the remaining sugar. You want to whisk it until the mixture turns pale yellow, becomes thick, and forms a ribbon when dripped on itself. (You can use an electric mixer with the whisk attachment if you are feeling lazy. It will take approximately 5 minutes of constant whisking by hand.)
Once the liquid mixture comes to a simmer, turn the heat off and let it sit for a minute or two. With the bowl containing the egg/sugar mixture secure on the counter (if no one is around to hold it, place it on a rubber mat or wet a dishtowel and wrap it around the base of the bowl), slowly pour the heated liquid mixture into the eggs, whisking constantly. Once fully incorporated, pour the contents of the bowl back into the saucepan. Over a medium-low heat, stir the mixture constantly with a wooden spoon until it reaches 185° F or a line holds when you drag your finger across the back of the wooden spoon. (It should only take a minute or two to reach the correct temperature.)
Immediately remove the saucepan from the heat and pour the cooked mixture through the strainer into the empty bowl sitting in the ice water bath. Lift strainer and discard the vanilla bean. (You can rinse off the vanilla bean in cold water and let it air dry completely for 24 hours. Save it for later use, such as to make vanilla sugar.) Continue stirring every few minutes as it sits in the ice bath until the mixture has completely cooled, about 10 minutes.
Pour into a container. Cover with plastic wrap directly over (touching) the mixture. Cover and place in refrigerator for 4-24 hours.
Follow your ice cream manufacturer’s directions to churn the ice cream. Transfer the ice cream to a freezer container. Cover with a piece of parchment paper or plastic wrap directly on the surface. Cover container and freeze.