Chill everything first. Put the Champagne and glasses in the fridge for at least 2 hours. Cold ingredients help keep the bubbles lively and the drink crisp.
Prep the passion fruit. If using fresh fruit, scoop out the pulp. If using frozen pulp, thaw it in the fridge.
Strain out seeds if you want a smoother sip, or leave some in for texture.
Mix the base. In a small pitcher or mixing glass, combine 1–1.5 ounces passion fruit pulp with 0.25–0.5 ounce fresh lime juice. Taste. If it’s too tart, add 0.25–0.5 ounce simple syrup.
For extra depth, add 0.25 ounce orange liqueur.
Build in the glass. Add 1–2 tablespoons of the passion fruit mixture to each chilled flute or coupe. You don’t need much—just enough to flavor the wine.
Top with bubbles. Slowly pour 4–5 ounces of Champagne into each glass, tilting slightly to preserve carbonation. Give a gentle stir with a bar spoon to combine.
Garnish and serve. Add a lime twist or a thin slice of passion fruit.
Serve immediately while it’s icy and sparkling.