Tear the bread into pieces into a bowl, pour over 150 ml (¼ pint) of the stock and leave to soak for 5 minutes until softened.
Grind the almonds and garlic together in a food processor or liquidizer until they form a fine powder then add the soaked bread with its stock, the oil, vinegar and a little salt and pepper. Blend together then gradually mix in the remaining stock.
Chill for at least 2 hours. Taste and adjust the seasoning if needed, then ladle into small bowls and sprinkle the grapes and flaked almonds to garnish. Serve with fresh ciabatta.