Step 1Prepare the figs the night before: Remove the stems. Cut the figs in very thin slices crosswise, then cut lengthwise to form very small pieces (less than 1/4 inch). There should be 1/2 cup. Place the figs in a bowl, add the mezcal and stir to mix. Cover and let stand overnight.
Step 2The next day, combine the eggs, sugar and salt in a bowl and beat until well mixed. Scald the milk in a saucepan over medium heat until it is barely bubbling, 4 to 5 minutes. Gradually beat it into the egg mixture. Turn the mixture into a saucepan and cook gently over medium-low heat, stirring constantly, until barely thickened, 6 to 8 minutes. Do not allow to boil. Strain the mixture through a sieve. Add the corn syrup, whipping cream and vanilla. Place the mixture in the refrigerator until cold, 1 to 2 hours. Stir in the figs and mezcal.
Step 3Process in an ice cream freezer following the manufacturer's directions. Spoon the ice cream into a container with a tight cover and place in the freezer 2 to 3 hours before serving.