1.Heat oil in a large saucepan; cook lamb, in batches, until browned. Remove from pan.
2.Cook onion and garlic in same pan, stirring, until onion softens. Add flour; cook, stirring, until mixture bubbles and thickens. Gradually add the water, stock and wine; stir until mixture boils and thickens.
3.Return lamb to pan with tomatoes, paste, bay leaves and rosemary; bring to the boil. Reduce heat; simmer, covered, 30 minutes.
4.Add celery, beans, carrots and mushrooms to pan; simmer, covered, 30 minutes or until vegetables are tender. Add peas; simmer, uncovered, until peas are just tender.
5.Remove and discard toothpicks from lamb. Serve navarin topped with parsley.
To freeze: Complete the recipe to the end of step 3. Pack into freezer-proof containers, leaving a 2.5cm (1 inch) space to allow for expansion. Seal, label and freeze for up to 3 months. Thaw overnight in the fridge. Reheat in a saucepan, then continue from step 4. Lamb noisettes are lamb sirloin chops with the bone removed and the “tail” wrapped around the meaty part of the chop and secured with a toothpick.