Place the stale bread slices in a bowl of cold water and leave for 5 minutes until completely softened and saturated. Squeeze out as much water as possible with your hands until the bread forms a compact, nearly dry mass. Set aside. This hydration and squeezing step is essential. Dry bread going into the blender produces an uneven, grainy texture in the finished soup.

Place the blanched almonds in a blender and blend alone, without any liquid, for a full minute until they form a fine, pale paste. This initial dry-blending step produces a dramatically smoother final texture and is almost never mentioned in modern recipes. The almonds need to break down into a flour-like consistency before liquid is introduced.

Add the squeezed bread, raw garlic cloves, olive oil, sherry vinegar and salt to the almond paste in the blender. Blend on high speed for a full 2 minutes until completely smooth. The mixture will be very thick at this point, almost paste-like. This is correct.

With the blender running, add the ice cold water gradually through the lid opening, stopping to check the consistency as you go. You are looking for something between single cream and a thick smoothie, pourable but substantial, not watery. The exact quantity will vary depending on how thick and dry your bread was. Stop and taste. Adjust salt and vinegar at this point. The soup should be sharp, rich and slightly pungent from the garlic.

Pass the soup through a fine mesh sieve into a large bowl, pushing it through firmly with the back of a spoon and working in batches. This step is not optional if you want the genuine article. Without sieving you have a rustic blended almond soup. With sieving you have something smooth, silky and remarkably white that is the correct ajo blanco. Discard whatever remains in the sieve.

Cover the sieved soup and refrigerate for a minimum of 2 hours. Overnight is significantly better. The flavour deepens and the raw garlic mellows considerably during the cold rest. A freshly blended ajo blanco tastes flat compared to one that has rested overnight.

Serve very cold in shallow bowls or glasses. The Málaga tradition is to thin the soup slightly further and serve it in glasses for drinking, which is the most historically grounded serving method. Place halved green grapes in the cold soup. Add a drizzle of olive oil across the surface and a few toasted almond slivers if you want the complete presentation.

Eat immediately. Ajo blanco is only itself when it is very cold.