This recipe can be made Pesach for a refreshing dessert after a heavy meal. Don’t leave out the black pepper—that’s what makes it exciting!
1 1/4 cups sugar
1 1/4 cups water
1 teaspoon grated grapefruit zest, optional
2 cups freshly squeezed red-grapefruit juice
2 tablespoons freshly squeezed lemon juice
1/2 teaspoon freshly ground black pepper
Combine the sugar, water, and grapefruit zest in a medium saucepan, and bring to a boil over medium-high heat, stirring occasionally until the sugar dissolves. Remove the pan from the heat and set it aside to steep for 5 minutes.
Stir in the grapefruit juice and lemon juice. Strain the mixture through a fine-mesh sieve into a bowl. Stir in the black pepper, and set it aside to cool. (It will cool faster if you set the container in a bowl of ice water and stir it intermittently.)
Cover and refrigerate the sorbet base until it is thoroughly chilled, about 4 hours or up to overnight.
Process the sorbet in a wide container and freeze 30 minutes. Using a hand blender or food processor, puree the mixture and return to the freezer. Freeze again for 30 minutes and puree once more.
Pack sorbet into an airtight freezer container, cover, and freeze until ready to serve.