1 Put the cucumber and broth in a blender and puree. Transfer the mixture to a glass bowl or plastic container; whisk in the yogurt, salt, and pepper until smooth. Cover the soup and refrigerate until chilled, at least 1 hour or up to 3 days.
2 Meanwhile, heat the oil in a large nonstick skillet over medium heat. Add the garlic and bread; cook, stirring frequently, until the bread is just toasted, about 6 minutes. Transfer the croutons to a plate and spread in a single layer; let cool. (The croutons can be stored in an airtight container up to 3 days.)