In a cocktail shaker, muddle fresh basil leaves to release their aromatic oils.

Add tequila, orange liqueur, blueberry syrup, lime juice, and ice cubes to the shaker.

Shake vigorously until well-chilled.

Strain the margarita into a salt-rimmed glass filled with ice.

Garnish with a basil leaf or a few fresh blueberries.

In a saucepan, combine 1 cup of water, 1 cup of sugar, and 1 cup of blueberries.

Place the saucepan over medium heat and stir the mixture gently until the sugar starts to dissolve.

Once the sugar has dissolved, increase the heat to bring the mixture to a gentle boil.

Reduce the heat to medium-low and let the mixture simmer for about 10-15 minutes, stirring occasionally.

As the blueberries soften and release their juices, the mixture will thicken into a syrup-like consistency.

Once the syrup has reached your desired thickness, remove the saucepan from the heat.

Let the syrup cool for a few minutes before transferring it to a heatproof container or jar.

If desired, you can strain the syrup through a fine mesh sieve to remove any solids and achieve a smoother consistency.

Allow the syrup to cool completely before using it in your favorite recipes or storing it in the refrigerator for future use.