Charred Rosemary–Infused Vodka

Char 1 large rosemary sprig in a dry skillet over medium-high heat, turning occasionally, until blackened in spots and fragrant, about 4 minutes. Place in a 1-quart glass jar and pour in one 750 ml bottle vodka (reserve bottle). Let sit at room temperature 24 hours. Taste it—you should be able to detect the flavor; if not, let infuse longer. Strain into reserved bottle and freeze at least 4 hours before serving.