Preheat broiler to low setting.
Place pears, sugar, cinnamon, and cardamom onto a baking sheet and toss together until pear is well coated.
Place under broiler for 3 to 4 minutes or until pears begin to caramelized.
Pour mixture into a blender and add lemon juice. Puree until smooth.
Strain mixture and chill for at least 30 minutes and up to an hour.
Divide pear juice between six glasses and top each with sparkling wine/champagne. Top with pear-flower garnish and serve.
For garnish: Using a ¼ inch melon baller, scoop out six small balls (skin-on)from one side of the pear. Set aside.
Slice a ¼ inch slice from the remaining sides of the pears. Place each slice cutside down onto a cutting board and thinly slice. Pierce three or four of the thin pear slices, and finish with a pear ball.