For the Oleo-Saccharum:
- Zest from 2 lemons
- Zest from 1 orange
- 4 1/2 ounces (130g) sugar
- For the Cocktails:
- 8 ounces (235ml) boiling water, plus more for preheating thermos
- 16 ounces (475ml) rye whiskey, such as Bulleit 95
- 4 ounces (120ml) unsweetened pomegranate juice
- 2 ounces (60ml) dry orange curaçao, such as Pierre Ferrand
- 8 dashes Angostura bitters
- 8 lemon zest strips, for garnish (optional)
For the Oleo-Saccharum: In a heatproof container with at least a 36-ounce capacity, toss together lemon and orange zests with sugar. Muddle for 30 seconds to release the oil from the zests. Cover and let stand at room temperature for at least 8 and up to 12 hours.
For the Cocktails: Pre-warm thermos by filling with water just off the boil and let stand. Meanwhile, pour rye whiskey, 8 ounces boiling water, pomegranate juice, orange curaçao, and bitters over the oleo-saccharum. Stir well until sugar is completely dissolved.
Discard hot water from thermos, then carefully strain rye mixture through a fine-mesh strainer into thermos (a funnel can help avoid spills); discard spent zests. Seal thermos. Optionally, when ready to drink, add new lemon zests to your cocktail, expressing the oils over the top first.