Combine milk, half-and-half and mint leave in a medium-sized, heavy saucepan, heat until tiny bubbles form around the edge. Remove from heat, cover and let stand for ten minutes. That gives the mint flavor time to steep. \t Uncover it and pour the mixture through a colander into a medium bowl. Press the mint leaves slightly with a big spoon to get all the flavor. Discard the leaves, and pour the liquid back into your pan. \t In a new bowl, combine sugar, salt and egg yolks. Stir with a whisk until the mixture is pale. \tGradually add half of the milk mixture to the egg mixture, while stirring constantly with a whisk. Pour the egg\/milk mixture back into the pan with the rest of the milk. \tCook over medium-low heat for about two minutes (or to 160 degrees), stirring constantly. \t Pour the ice cream mixture into a container that you've popped in the freezer previously to get nice and chilled. Store in the coldest part of your freezer until almost firm, but still soft enough to be stirred. For the next three hours, check the ice cream every 30 minutes and stir or mix with a hand mixer to keep it aerated and creamy.