Shake fernet, gin, lemon juice and strawberry syrup with ice. Strain into coupe glass, top with champagne, cava or sparkling wine. Garnish with lemon peel.
I use Letherbee for the gin and the fernet, but you do you. I can't tell you how to live your life.
A cross between the Rabbit Hole (see http://imbibemagazine.com/rabbit-hole-fernet-cocktail/) and Bitter Herb (see http://www.kindredcocktails.com/cocktail/bitter-herb).