Nibblous | prawns with mustard and fresh coriander

Ingredients

• 1 oz (25gm) butter
• 2 teaspoons sesame oil
• 2 sticks celery, chopped
• 1 clove garlic, peeled and crushed
• 1lb (500gms) frozen prawns, defrosted and drained (pat dry with paper towel, but don't let bits of paper get stuck to the prawns!)
• 3 tablespoons fish stock (if you don't have this, use water or veg stock)
• 3 teaspoons Dijon mustard
• 2 tablespoons medium dry sherry
• 11/2 level tablespoons cornflour
• 5fl oz (142ml) carton double cream
• 1-2 tablespoons chopped fresh coriander leaves