Pour the milk and heavy cream into a saucepan. Heat on medium heat until warm but not boiling. Stir gently while heating so the mixture does not burn.

In a bowl, whisk egg yolks and sugar together. Continue mixing until the mixture looks pale and slightly thick. This step helps create a smooth ice cream base.

Slowly pour a small amount of warm milk mixture into the egg mixture. Whisk constantly while pouring. This step prevents the eggs from scrambling.

Pour the egg mixture back into the saucepan. Cook on low heat. Stir constantly with a spatula until the mixture thickens slightly and coats the spoon.

Remove the saucepan from heat. Add vanilla extract, almond extract, raspberry extract, lemon extract and a pinch of salt. Mix well so the flavors blend evenly.

Add a few drops of blue food coloring. Stir gently until the mixture becomes bright blue. Adjust color if needed to get the classic Blue Moon look.

Cover the mixture with plastic wrap. Place it in the refrigerator for at least 3 hours. This step helps the flavors develop and improves the texture.

Pour the chilled mixture into an ice cream maker. Churn according to the machine instructions. The mixture will slowly turn thick and creamy.

Transfer the churned ice cream to a freezer-safe container. Cover tightly and freeze for about 3 hours until firm and scoopable.