Step 1

Put the garlic, green pepper, tomatoes, bread, olive oil, vinegar, and salt in a food processor. Pulse until the ingredients begin to purée (if the bread is hard, it may bounce about and take a while to break down); continue processing until the mixture is as finea purée as possible, 3 to 5 minutes.

Step 2

Pass the soup through a large fine sieve set over alarge bowl, pressing until only solids remain in the sieve; discard the solids. Stir in 1/4 to 1/2 cup ­water, or enough to give the soup the consistency of a thin milkshake. If you want a thicker soup, add less water, or none at all. Add more salt or vinegar to taste. Cover and refrigerate until well chilled (or serve it ­immediately with a few ice cubes in each bowl).

Step 3

Ladle the gazpacho into chilled bowls or cups. Grind fresh pepper on top, if you want, and pass bowls of diced cucumber and onion, if using, so ­people can garnish their own.