Heat the oil in a large pan over a medium-high heat. Add the onion, celery and carrot and cook, stirring for 5mins
Add the tomatoes, ham, stock and mustard to pan and bring to the boil. Reduce the heat to low and simmer for 10mins or until the vegetables are tender and the soup has reduced slightly
Add the lentils, beans, zucchinis and peas to pan and simmer for 5mins or until the beans are tender. Serve sprinkled with parsley