Combine water and sugar in a small pot over medium heat. Add cinnamon sticks. Stir until sugar dissolves completely, about two minutes. Let the mixture simmer for five minutes to infuse the cinnamon flavor into the syrup. Remove from heat and let it cool completely before using. You can make this up to two weeks ahead and store in the refrigerator.

Mix granulated sugar with ground cinnamon on a small plate. Run a lime wedge around the rim of your cocktail glass to moisten it. Dip the rim into the cinnamon sugar mixture and twist gently to coat evenly. Set the prepared glass aside while you mix the margarita.

Fill a cocktail shaker with ice. Add tequila, orange liqueur, fresh lime juice, cranberry juice, and cinnamon simple syrup to the shaker. Make sure all your measurements are accurate for the best balanced flavor in your spiced Christmas margarita.

Close the shaker tightly and shake vigorously for about fifteen seconds. You want to shake until the outside of the shaker feels cold and frosty. This properly chills and dilutes the cocktail while mixing all the flavors together perfectly.

Fill your prepared glass with fresh ice. Strain the margarita from the shaker into the glass over the ice. The strainer catches any ice chips or pulp from the lime juice for a smooth cocktail.

Grate a tiny amount of fresh nutmeg over the top of the drink using a microplane or fine grater. Add your choice of garnishes like fresh cranberries, an orange slice, a rosemary sprig, or a cinnamon stick. These make your holiday margarita look festive and add subtle aromatics.

Serve your spiced Christmas margarita immediately while it's ice cold. The drink is best enjoyed fresh when the ice hasn't melted and diluted the flavors. Enjoy this festive cocktail at your holiday party or cozy winter gathering.