This subtle soupy dish is actually a combination of two Keralan dishes, vegetable stew (ishtoo) and rice noodles (iddiyapam).
Boil the potatoes in a pan of salted water until tender, then drain well, and mash with a potato masher or ricer until smooth, and set aside.
Meanwhile, heat the oil in a large saucepan over a medium heat. Add the peppercorns, cinnamon, and cloves, and fry for 20 to 30 seconds, or until the spices are fragrant. Add the onion, and fry for 3 to 4 minutes, or until softened and golden brown.
Add the curry leaves, chiles, and ginger, and cook for a further 20 to 30 seconds. Season the mixture, with salt, and freshly ground black pepper. Add the cauliflower and broccoli florets, and then add enough of the boiling water to cover the ingredients. Bring the mixture to a boil, and cook for 5 to 6 minutes, or until the florets are just tender. Add the green beans, mashed potato, peas, and 1 cup boiling water, and stir until the mashed potato has absorbed all of the water, and the mixture is thick, and well combined.
Bring the mixture to a boil, then reduce the heat to a gentle simmer, and add the coconut milk and garam masala. Season the mixture, to taste, with salt, and freshly ground black pepper.
To serve the dish, divide the cooked noodles among four serving bowls, and spoon over the vegetable stew. Garnish with the chopped cilantro.