In a medium saucepan, combine the heavy cream, whole milk, sugar, and salt. Heat over medium heat until warm and sugar has dissolved, stirring occasionally. Do not let it boil.

Remove from heat and add fresh mint leaves. Cover and let steep for 30 minutes.

Strain the mixture through a fine-mesh sieve into a clean bowl, pressing on the mint leaves to extract flavor. Discard the mint leaves.

In a separate bowl, whisk the egg yolks until pale and slightly thickened. Gradually add about 1 cup of the warm cream mixture to the egg yolks, whisking constantly.

Return the egg yolk mixture to the saucepan with the remaining cream mixture. Cook over low heat, stirring constantly, until thickened, about 5-7 minutes. Do not let it boil.

Remove from heat and stir in vanilla extract. Allow to cool to room temperature, then cover and refrigerate for at least 4 hours or overnight.

Churn the mixture in an ice cream maker according to manufacturer’s instructions. Transfer to an airtight container and freeze for at least 4 hours before serving.