Prepare Sugared Cranberries (Optional): In a small bowl, gently toss the frozen cranberries with the granulated sugar until they're beautifully coated and glistening. Set them aside to sparkle.
Rim Your Glasses (Optional): For a festive presentation, take a lime wedge and run it around the rim of your serving glasses. Then, dip the moist rims into a shallow plate filled with granulated sugar to create a sparkling sugar rim.
Mix the Pitcher Margarita: In a large pitcher, combine the Reposado Tequila, Cointreau, fresh lime juice, and cranberry juice. Stir everything together thoroughly until well blended. Taste the mixture, and if you prefer it sweeter, add a little agave nectar and stir again.
Chill and Serve: You can either store the pitcher in the refrigerator until you're ready to serve, allowing the flavors to deepen, or serve it immediately. Fill your prepared, sugar-rimmed glasses with plenty of ice.
Garnish and Enjoy: Pour the vibrant Holiday Cranberry Margarita over the ice in each glass. Complete the festive look by adding a fresh rosemary sprig, a thin lime slice, and a few of your sparkling sugared cranberries to each drink. Serve immediately and savor this easy, healthy, and festive holiday cocktail!