Place almonds, garlic, water, and white bread in a blender. Blend on high until the mixture is very smooth. Stop and scrape down the sides if needed.

Add salt, sherry vinegar, and olive oil. Blend briefly until everything is combined and the soup is creamy. If the soup is too thick, add a little more cold water to reach your preferred consistency. If desired, pass the soup through a fine mesh strainer.

Transfer the soup to a sealed container and refrigerate for at least 2 hours. Before serving, give the soup a good stir.

Serve cold in bowls and garnish with halved green grapes, a sprinkle of toasted almonds, and a few fresh mint leaves. Drizzle a little extra olive oil if desired.