Bring to a gentle simmer over medium heat, stirring until sugar dissolves. Simmer for 8–10 minutes until the rhubarb breaks down and the liquid is pink and fragrant.

Remove from heat and let steep for 10 minutes to intensify flavor.

Strain through a fine mesh sieve into a heatproof container, pressing on solids to extract syrup. Discard solids. Cool to room temperature, then refrigerate. Yields about 1 cup; use 0.5 oz per cocktail.

Cocktail assembly

Chill glass

If desired, chill a coupe or rocks glass by filling with ice water while you prepare the cocktail.

Fill a cocktail shaker with ice (about 4 cubes).

Add 1.5 oz Zucca (or chosen amaro), 0.5 oz bitter orange liqueur, 0.5 oz rhubarb syrup, and 0.5 oz fresh lemon juice to the shaker.

Shake vigorously for 12–15 seconds until well chilled and slightly diluted.

Discard ice water from the chilled glass (if used). Strain the cocktail into the chilled coupe or over fresh ice in a rocks glass, depending on preference.

If you prefer a lighter finish, top with 1 oz sparkling water; otherwise serve neat.

Garnish with a thin rhubarb ribbon or an orange peel twist and, if using, a small sprig of thyme laid on top for aroma.

Serve immediately.