Which cocktail is made with equal parts clear Creme de cacao and green Creme de menthe?

The Grasshopper is a classic cocktail known for its distinctive green color and minty flavor. The key ingredients in this cocktail are equal parts clear Creme de cacao and green Creme de menthe, along with cream or milk, which contributes to its rich and creamy texture. The balance of the sweet chocolate notes from the clear Creme de cacao and the refreshing herbal qualities of the green Creme de menthe creates a delightful and smooth drink perfect for dessert or as a sweet treat.

The other cocktails mentioned do not contain the same combination of ingredients in equal proportions: the Champagne Cocktail is typically made with champagne and a sugar cube, the Muddled Old Fashioned focuses on whiskey and bitters with muddled sugar and fruit, and the Kir Royal features champagne with crème de cassis. Therefore, the Grasshopper's specific ingredients and preparation method clearly align with the details given in the question.