Add the half and half to a small pot on medium heat. Bring it to a low simmer and then turn off the burner.
Add your egg yolks and 1/4 cup sugar to a heat proof bowl and whisk together.
Then slowly pour the hot half and half into the bowl. Whisk constantly.
Once it has been combined pour the mixture back into the saucepan. Continue to whisk over low heat until it thickens a bit. (180°F) To check: dip the back of a spoon into the mixture. The creme should evenly coat it without dripping off.
Pour the custard through a mesh strainer to remove any lumps/skin that can form.
Add vanilla and stir well. Cover the creme and place it in the fridge to chill.