Prepare the mint ice cream base: Combine the heavy cream, milk, and fresh mint leaves in a medium saucepan. Heat over medium-low heat until steaming but not boiling, then remove from heat and let the mint steep for 30 minutes.

Strain the mint-infused cream mixture through a fine mesh sieve, pressing on the mint leaves to extract all flavor. Discard the mint leaves.

In a separate bowl, whisk together the egg yolks and 3/4 cup sugar until pale and creamy.

Gradually whisk the warm cream mixture into the egg yolks, a little at a time, to temper the eggs.

Return the mixture to the saucepan and cook over low heat, stirring constantly with a wooden spoon, until the mixture thickens slightly and coats the back of the spoon. Do not let it boil.

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

Churn the chilled ice cream base in an ice cream maker according to the manufacturer’s instructions. Transfer the ice cream to an airtight container and freeze for at least 2 hours before serving.

Prepare the salted watermelon granita: Puree the cubed watermelon in a blender until smooth. Strain through a fine mesh sieve to remove pulp, if desired.

Stir in 2 tablespoons sugar and 1/4 teaspoon sea salt until dissolved.

Pour the watermelon mixture into a shallow, freezer-safe dish. Freeze for 30 minutes, then scrape the mixture with a fork to create icy flakes. Repeat this process every 30 minutes for 3 hours, scraping with a fork each time, until the granita is fully frozen and flaky.

To serve: Scoop the fresh mint ice cream into bowls or glasses and top with generous spoonfuls of salted watermelon granita. Garnish with a sprig of fresh mint if desired.