Heat vegetable stock in a non-stick wok. Cut potato into medium sized cubes and add to the wok. Similarly cube carrot and add to the wok. Cover and cook.
Cube yellow zucchini.
Tie up cloves, cumin seeds and black peppercorns in a piece of muslin cloth, crush slightly and add to the wok.
Cube onion. Add cauliflower, onion, yellow zucchini and green zucchini to the wok and mix. Add salt and freshly crushed black peppercorns and mix. Cover and cook. Add garlic cloves and celery.
Mix whole wheat flour with ¼ cup water till smooth and add to the vegetables. Add green peas and mix. Cover and cook till the vegetables are soft. Remove the spice potli.
Add buttermilk and mix. Tear spinach leaves and add to the wok and mix well.
Transfer into a serving bowl and serve hot with brown bread or steamed brown rice.