A few drops of lavender essential oil can be substituted in lieu of dried lavender. Using dried lavender will result in tiny pieces of the flower in the drink (as pictured) even if you fine mesh strain it. To prevent this, use a fine mesh strainer lined with cheesecloth.
1 oz. Bombay Sapphire gin
.75 oz. St. Germain elderflower liqueur
3/4 bar spoon of dried lavender
.5 oz. simple syrup
.5 oz. Chambord raspberry liqueur
Shake all ingredients except tonic water until very cold. Fine mesh strain (if using dried lavender) into a Collins glass with ice and top with tonic water. Garnish with lemon peel.