Normally served cold as a sweet cinnamon-and-rice drink, horchata translates seamlessly to this creamy dessert.
- 2 cups brown basmati or other long-grain brown rice
- 3 tablespoons crushed cinnamon sticks, preferably Ceylon
- ¾ teaspoon kosher salt, plus more
- 4 cups heavy cream
- 3 large egg whites
- ⅔ cup granulated sugar
- Nonstick vegetable oil spray
- 3 cups puffed kamut or puffed rice cereal
- ½ cup (packed) light brown sugar
- 5 tablespoons unsalted butter
- ¼ cup tequila reposado
- 2 tablespoons light corn syrup
Blend rice, cinnamon, and ¾ tsp. salt in a blender to a fine powder. Stir rice mixture and cream in a large bowl until no lumps remain; cover and chill at least 3 hours and up to 6 hours. Strain through a fine-mesh sieve into a large bowl, pressing on solids; reserve rice for another use.
Using an electric mixer on high speed, beat cream in a large bowl to stiff peaks, about 3 minutes; set aside.
Whisk egg whites, granulated sugar, and a pinch of salt in a medium heatproof bowl set over a saucepan of simmering water (do not let bowl touch water). Cook, whisking constantly, until sugar is dissolved and an instant-read thermometer inserted into the mixture registers 130°, about 4 minutes. Remove bowl from heat and, using an electric mixer on high speed, beat until mixture is tripled in volume, glossy, and cool, 10–12 minutes (this will take only about 6 minutes if using a stand mixer fitted with whisk attachment).
Gently fold reserved cream into meringue until mixture is smooth. Scrape into an 8×8″ baking pan; cover and freeze until set, at least 3 hours.
Meanwhile, lightly coat a large heatproof bowl with nonstick spray. Place kamut in bowl. Bring brown sugar, butter, tequila, and corn syrup to a boil in a medium saucepan, stirring to dissolve sugar. Cook, stirring often, until caramel is a deep amber, 10–12 minutes. Quickly pour caramel over kamut and mix with a heatproof spatula to coat. Transfer to a parchment-lined rimmed baking sheet and let cool. Break into small pieces.
Scoop semifreddo into bowls and top with caramel kamut.
Do Ahead: Semifreddo can be made 3 days ahead; keep frozen. Let sit at room temperature 30 minutes before scooping. Caramel kamut can be made 1 day ahead; store airtight between layers of paper towels at room temperature.