June 19, 1865, or Juneteenth, is the day more than 200,000 enslaved Texans received the word that rippled from Galveston, Texas, to the entire Lone Star State that they were free—more than two years after President Lincoln signed the Emancipation Proclamation. In 1866, on the one-year anniversary of the announcement, Texas newspapers reported on celebratory whole-hog barbecues that Black Americans held. The journalists wrote with vivid details about seeded watermelon flanking the billowy smoke. This slushy is a celebration of bright red watermelon as a symbol of tradition. Summer doesn’t begin until a watermelon is cracked open. Here, it’s paired with equally refreshing and summer-abundant cucumber, a light tang of Champagne vinegar, and a lick of salt. This is a bright and balanced thirst quencher you’ll enjoy on Juneteenth and all of the hot days thereafter. For the smoothest slushy, please pound your ice to a crushed state before adding it to a high-powered blender; the end result should be spoonable, like soft ice cream.