Add a little tequila and Cointreau to this refreshing mocktail for a berrylicious adult slushie.
Wash the jars in hot, soapy water and dry thoroughly. Alternatively, run the jars through the regular cycle of your dishwasher; wash the rubber gaskets by hand.
Combine the sugar and water in a small saucepan and bring
to a boil over medium-high heat, stirring to dissolve the sugar.
Add the basil, decrease the heat, and simmer for 2 minutes.
Remove the pan from the heat and set aside to cool. Using a
fine-mesh strainer, strain the simple syrup into a blender. Discard
the basil.
Add the blueberries, blackberries, and lime and lemon juices
to the blender. Holding the blender lid securely in place, blend
the mixture on high speed until puréed. Using a fine-mesh
strainer set over a medium bowl, strain the berry purée to
remove all the seeds. Using a rubber spatula, press down to
extract all the purée. Discard the seeds.
Using a wide-mouth funnel and filling one jar at a time, ladle the margarita base into the prepared
jars, leaving 1 inch headspace. Wipe the rims clean and secure the lids. Label and refrigerate until ready to serve.
Tequila version: To add a cool touch, as well as whimsy and fun, to a backyard party, blend the base together with premium silver tequila and a touch of Cointreau in an ice-cream maker. Serve in a chilled margarita glass rimmed with sugar and garnished with a wheel of lime.
Storing: Refrigerate for up to 10 days, or freeze for up to 3 months.
