Spread the almonds in a pie plate and toast for 6 minutes, until lightly golden; let cool. Transfer 1 cup of the almonds to a blender. Add the bread, cucumber, apple, grapes, garlic, vinegar and 1/4 cup of olive oil. Puree until smooth. Strain the soup through a sieve into a bowl, pressing on the solids. Whisk in the buttermilk and season with salt and pepper. Refrigerate until chilled, at least 30 minutes.