Step 1: Prepare the Berry Basil Simple Syrup. In a medium saucepan, combine 1 cup of granulated sugar and 1 cup of water. Heat over medium heat, stirring until the sugar is completely dissolved.
Step 2: Add 1 cup of mixed berries and 1/4 cup of fresh basil leaves (lightly torn) to the saucepan. Bring to a gentle simmer and let it cook for about 5 minutes, gently mashing the berries with the back of a spoon to release their juices.
Step 3: Remove the saucepan from the heat. Carefully strain the berry and basil mixture through a fine-mesh sieve into a heat-proof bowl or jar, pressing on the solids with a spoon to extract all the liquid. Discard the solids.
Step 4: Allow the simple syrup to cool completely. You can speed this up by placing the bowl in an ice bath.
Step 5: Squeeze about 6-8 large lemons to yield approximately 1.5 cups of fresh lemon juice. This amount can be adjusted to your preference for tartness.
Step 6: In a large pitcher, combine the cooled berry basil simple syrup and the freshly squeezed lemon juice. Stir well to ensure everything is thoroughly mixed. This is your concentrated lemonade base.
Step 7: When ready to serve, fill individual glasses with ice. Pour about 1/2 to 3/4 cup of the lemonade concentrate into each glass, then top with chilled sparkling water (or plain water if you prefer).
Step 8: Garnish with fresh berries, a slice of lemon, and a sprig of fresh basil. Give it a gentle stir and enjoy your refreshing summer drink.