Sweet Potato Sour Recipe

1. Prepare sweet potato purée

Peel and dice 1 small sweet potato (about 6–8 oz). Steam or boil until very tender, about 12–15 minutes. Drain well, then press through a fine-mesh sieve or blend until very smooth. Measure 1/2 cup and cool to near room temperature before using. If purée seems very thick, thin with up to 1 tablespoon water.

2. Dry shake (no ice) the sweet potato purée, rye whiskey, lemon juice, lime juice, simple syrup and egg white in a cocktail shaker for 20–30 seconds. This whitens and emulsifies the egg white and incorporates the purée into a silky foam.

3. Add ice to the shaker and shake vigorously for 15–20 seconds more until well chilled and the shaker is frosty.

4. Double-strain the cocktail through a fine-mesh strainer into a chilled coupe or Nick & Nora glass to remove any fibrous bits from the purée and to achieve a velvety texture.

5. Add 2 dashes of Angostura bitters to the foam surface. Use a toothpick to swirl or create a small design if desired.

6. Grate the Indonesian long black pepper: place the 2 whole pepper grains on a microplane or very fine grater and grate directly over the finished cocktail foam to release an aromatic, slightly floral-camphor spice. A little goes a long way; about a fine dusting is enough.

7. Optional: If using, garnish with a thin candied sweet potato slice laid across the rim or floated on the foam. To make quickly: thinly slice sweet potato on a mandoline, simmer in equal parts water and sugar until tender and glossy (3–5 min), then drain and chill before using.

8. Serve immediately. Encourage guests to inhale the grated long pepper aroma before sipping to appreciate the aromatic top-note against the sweet potato and citrus foundation.