This full-flavor frozen treat will keep you cool all summer.
4 to 5 large ripe tomatoes (about 2 pounds), preferably heirloom, stemmed and halved crosswise
1 tbs. sherry vinegar
1 tbs. fresh lemon juice
1 to 2 tbs. agave syrup (depending on the ripeness of the tomatoes)
1 tsp.kosher salt, plus more if needed
1. Place a large fine-mesh sieve over a large bowl. Squeeze one tomato half into the sieve, squashing it to release as much juice and pulp as possible. Use a rubber spatula to press the pulp through the sieve. Discard the skin and seeds. Repeat with the remaining halves; you should end up with about 2¾ cups of tomato liquid. To the liquid, stir in the sherry vinegar, lemon juice, agave syrup and kosher salt to taste.
2. Transfer the mixture to a non-reactive, medium-size square container. Freeze until the edges of the mixture begin to harden, about 1 hour, then drag a fork through the mixture to break it up into smaller ice crystals. Repeat every 30 minutes until the granita is fully frozen and fluffy in texture, about 3 hours total. Divide into small bowls and serve.