How to Make It
Preheat the oven to 400°. On a large rimmed baking sheet, toss the sunchokes, carrots, parsnips, sweet potatoes, shallots, olive oil, lemon zest, ginger, cinnamon, turmeric and crushed red pepper. Season generously with salt. Roast the vegetables for about 30 minutes, until tender and browned in spots.
Stir 1 cup of the water into the vegetables and scatter the currants and bay leaf on top. Roast for about 10 more minutes, until the currants are plump and the vegetables are saucy. Discard the bay leaf.
Meanwhile, put the couscous in a large heatproof bowl. In a small saucepan, bring the remaining 1 1/4 cups of water to a boil with the butter. Remove from the heat, add the saffron and a generous pinch of salt and let stand for 5 minutes. Bring the water back to a boil and pour it over the couscous. Cover the bowl with plastic wrap and let stand for 10 minutes. Fluff the couscous with a fork and season with salt.
Transfer the couscous to plates and spoon the roasted vegetables and their juices on top. Garnish with chopped cilantro and pistachios and serve.