Shake all ingredients (except soda) with ice. Strain over ice into a highball glass. Fill with soda water, garnish with lemon peel.
Grenadine: 2 cups pomegranate (I used POM, but I understand juicing with a lever juicer works as well). 1.5 ounce sugar. 2 ounces pomegranate molasses. 1 tablespoon orange blossom water. Shake well until sugar dissolves (I run the bottle under hot water to help).