Heat the oil in a large saucepan, add the onions and celery and fry gently for 5 minutes. Do not allow the vegetables to brown.

Add the carrots and mushrooms to the pan and continue cooking for a further 5 minutes, stirring from time to time.

Remove from the heat, then stir in the peanut butter until well combined. Add the peanuts, wholemeal breadcrumbs, herbs and salt and pepper to taste. Mix well and bind with half the beaten eggs. Leave until cool enough to handle.

Meanwhile, pour the remaining beaten eggs into a shallow bowl or on to a plate. Place the dried breadcrumbs on a separate plate, ready to coat the croquettes.

When the mixture is cool, divide it into 16 portions and shape them into croquettes. Dip each croquette in the beaten eggs, then roll in the breadcrumbs until thoroughly coated.

Pour enough vegetable oil into a deep-fat frier to come to a depth of 4 cm (1 1/2 inches). Heat to 180C/350F or until a 2.5 cm (1 inch) bread cube browns in 60 seconds. Lower in the croquettes and deep-fry for 3 minutes, until golden brown. Drain the croquettes very thoroughly on absorbent paper and serve hot.