Place the cranberries into the cocktail shaker and gently muddle them for about 15 seconds until they release their deep red juice and aroma, creating a vibrant pulp.
Add the orange liqueur, cranberry juice, and simple syrup to the shaker with the muddled cranberries.
Fill the shaker with ice, then close it tightly and shake vigorously for about 10–15 seconds until the mixture is well chilled and slightly diluted, with a frothy top forming.
Place the fine strainer over a tall flute and strain the mixture into the glass, catching the cranberry bits for a smooth, bright red drink.
Gently pour the sparkling wine into the glass, pouring slowly down the side to preserve the bubbles and create a lively, effervescent top.
Garnish with a few cranberries or a twist of orange peel to add a visual pop and aromatic finish.
Serve immediately and enjoy the bright, sparkling celebration of early winter mornings with this festive cranberry mimosa.