Step 1

In a small saucepan over medium heat, combine milk, heavy cream, sugar and salt. Stir to dissolve sugar. Remove milk mixture from heat. Cover and chill thoroughly, at least 4-6 hours or overnight.

Step 2

Stir in lime juice and optional food color prior to churning.

Step 3

Churn according to manufacturer's directions.

Step 4

Transfer mixture to a freezer safe container. Freeze until firm or desired consistency is reached.