Happy New Year Kumquat Cocktail

Ingredients (for 4 cocktails)
1 and 1/4 cup thinly sliced kumquats, plus more for garnish
1/3 cup grand marnier
1/4 cup of sugar
1 750 ml bottle of chilled champagne (or other bubbly)

In a small bowl muddle the first three ingredients together with the back of a spoon.
Let sit for 10 minutes. Strain liquid through a fine mesh strainer.
Pour two tablespoons of kumquat liqueur into champagne flutes and top with champagne.
Garnish with sliced kumquats.