Place the pear slices in a cocktail shaker. Use a cocktail muddler or the end of a rolling pin to crush slightly. Add the vodka, agave syrup, yuzu juice, pomme verte and egg white to the shaker. Add some ice. Place the lid and shake for 30 seconds to combine and chill. Strain into an ice-filled rocks (lowball) glass. Decorate with extra pear slices, skewered and fanned,