BLACK RICE HORCHATA ICE CREAM // makes 1-quart
1-1/2 cups black rice (aka heirloom forbidden rice)
4 cups whole milk
1/2 cup almonds, lightly crushed, most left whole
2 cinnamon sticks
2 cups mascarpone cheese
3/4 cup granulated cane sugar
1/4 teaspoon Kosher salt
3 large egg yolks
1 teaspoon vanilla bean paste or vanilla extract
1-3/4 teaspoons ground cinnamon
In a blender, pulse the milk and 1/4 cup of rice on medium-low just until the rice is lightly ground, about 8 seconds. Strain the milk from the ground rice into a bowl, discard the rice, and set aside. In a large saucepan, toast the remaining 1 1/4 cups of rice, almonds, and cinnamon sticks over medium heat for about 4 minutes until fragrant. Pour in all except 1 cup of the rice milk mixture to set aside. Bring to a boil, and let simmer on low until the milk has turned a deep purple hue, about 15-20 minutes.
Meanwhile, in a large saucepan, whisk together the mascarpone, sugar, and salt. Place over medium heat, bring to a simmer, and cook stirring occasionally, until the sugar dissolves and the mixture is hot, about 5 to 7 minutes. Turn off the heat and let cool slightly.
Add the remaining 1 cup of milk, egg yolks, vanilla, and cinnamon to the mascarpone-sugar mixture and whisk until incorporated. Strain the purple milk into the custard (there should be about 1-1/2 to 2 cups of milk remaining after straining the slightly cooked rice), turn the heat to medium-low, and cook, stirring, until the custard thickens enough to coat the back of a spoon and registers 170-175ºF on an instant read thermometer. Strain the custard once more into a bowl to ensure it’s entirely smooth and free of clusters. Cover with plastic wrap and refrigerate until well chilled, at least 6 hours or up to overnight. (You can speed the cooling process by nestling the bowl in an ice bath and stirring from time to time.)
Pour the custard into an ice cream maker and freeze according to the manufacturer’s instructions. Transfer to an airtight container and freeze for at least 6 hours and up to 2 weeks.