1. Add ice to a cocktail shaker, and pour in prickly pear lemonade and Tito’s.
2. Shake until chilled.
3. Strain and pour over ice into a highball glass.
4. Top with lemon soda water.
5. Garnish with melon balls and blueberries on a pick, and add a fresh sprig of mint.

For the prickly pear lemonade:

1. Squeeze and strain fresh lemons to yield 2/3 cup juice.
2. Squeeze and strain fresh limes to yield 1/3 cup juice.
3. Stir the lemon and lime juices, prickly pear simple syrup, agave nectar, and water together into a container.
4. Store in the refrigerator.

For the prickly pear simple syrup:

1. Hold the thornless prickly pears with tongs and cut them in half.
2. Using a spoon, scoop out the fruit pulp.
3. Add the fruit pulp to a medium saucepan with the water and sugar.
4. Bring to a gentle boil, then reduce to a medium-low and simmer for about 25-30 minutes.
5. Remove the saucepan from the heat and let it come to room temperature.
6. Add the syrup mixture into a blender and blend until smooth.
7. Pour the mixture through a fine mesh strainer into a container and stir in the lime juice to combine.
8. Store in the refrigerator.