If using rosemary: On a fire safe surface, light the rosemary on fire until it begins to smoke. Put your glass upside-down over the rosemary to trap all of the smoke to infuse the glass.
In a bar mixing tin, add the chardonnay, St. Germain, lemon juice and preserves. Add ice until level with the liquid. Shake vigorously for 30 seconds.
Strain into your glass and float the rosemary sprig on top of the cocktail.
Using a small sifter, shake powdered sugar all over the rosemary and rim of the glass. Enjoy immediately.
Notes
I used cranberry preserves to keep it festive but use whatever berry preserves you like.