1. In a stand mixer bowl add egg yolks and 1 cup sugar. Mix until mixture is light in color and creamy.
2. In a heavy bottom sauce pan add milk, whipping cream, salt, and 4 tablespoons sugar. Stir to combine. Heat mixture over medium heat and cook until small bubbles appear on sides (do not bring to boil). Remove from heat.
3. Gradually and slowly add egg mixture to liquid, stirring as you go. Return pan to heat and cook over medium heat until mixture thickens and coats the back of a wooden spoon. Remove from heat.
4. Allow pan to come to room temperature OR place over an ice bath to cool it more rapidly. Add mint sprigs.
5. Transfer to refrigerator and allow to chill completely.
6. Prior to churning remove and discard mint sprigs. Churn mixture according to your machine’s manufacturer’s directions. During last 5 minutes of churning slowly add in mini morsels.