For simple syrup, heat 1 cup each water and sugar in a saucepan, stirring, until sugar dissolves. Let cool, and store in the refrigerator.
- 2 tablespoons fresh blood orange juice, plus 1 orange peel twist
Muddle tarragon at the bottom of a cocktail shaker. Add remaining ingredients except for champagne, fill with ice, and shake well. Double strain into a champagne coupe or flute. Top with champagne and blood orange peel.