+ 8 ounces stemmed and pitted cherries, fresh or frozen + 1/3 cup confectioners’ sugar + 2 teaspoons freshly squeezed lemon juice + 2 tablespoons silver or blanco tequila + 1 1/2 cups whole milk + 1/2 cup granulated sugar + 1/4 teaspoon salt + 1 vanilla bean, split lengthwise, or 1 teaspoon pure vanilla extract + 1 1/2 cups sour cream
Put the cherries in a nonreactive saucepan with the confectioners’ sugar and cook over medium heat, stirring, until the mixture comes to a boil and the sugar has dissolved. Lower the heat, stir in the lemon juice, and simmer, stirring often, until the syrup has thickened and has a consistency like maple syrup. Remove from the heat, stir in the tequila, and refrigerate until completely chilled.
Drain the cherries, reserving the liquid for another use (soda!). Combine the milk, granulated sugar, and salt in a medium saucepan. If using vanilla bean, scrape the seeds into the mixture, then add the pod. Cook over medium heat, stirring, until the sugar has dissolved and the mixture just comes to a boil.
Remove from the heat, add the sour cream, and stir with a whisk until completely smooth. If using vanilla extract, stir it in at this point. Let cool slightly, then discard the vanilla bean and refrigerate the mixture until completely chilled.
Put a bit of the sour cream mixture into each of your molds, to a height of about 1 inch. Freeze until the mixture begins to set, about 30 minutes. Divide the drained cherries among the molds, then pour in the remaining sour cream mixture, dividing it evenly among the molds.