Position a rack in the center of the oven and preheat it to 425°F (220°C). Line a 13-by-18-inch (33-by-46-cm) rimmed baking sheet with parchment paper.

Combine the rinsed quinoa, 2 cups water, and 1/4 teaspoon salt in a medium saucepan. Bring to a boil over medium-high heat. Reduce the heat to low, cover, and simmer for 15 minutes, or until the water is absorbed and the quinoa grains have opened into small spirals.

Remove the saucepan from the heat and let the quinoa stand, covered, for 5 minutes. Fluff it gently with a fork. If water remains in the bottom, return the pan to low heat uncovered for 1 to 2 minutes.

Place the sweet potato, chickpeas, and broccoli on the prepared baking sheet. Drizzle with the 2 tablespoons olive oil, then sprinkle with the turmeric, cumin, garlic powder, salt, and black pepper. Toss until everything is evenly coated.

Spread the ingredients into a single layer. Place the sweet potatoes cut-side down where possible and leave space between the broccoli florets and chickpeas. An overcrowded pan will steam the vegetables instead of browning them.

Roast for 25 to 30 minutes, stirring after 15 minutes. The sweet potato should be tender when pierced with a fork, the broccoli should have browned tips, and the chickpeas should feel dry and lightly crisp on the outside.

While the vegetables roast, place the sliced kale in a large bowl. Add 1 tablespoon lemon juice and 1 teaspoon olive oil. Massage with clean hands for 1 to 2 minutes, until the kale becomes darker, glossier, and slightly reduced in volume. It should feel tender but not limp.

Whisk the tahini, 3 tablespoons warm water, lemon juice, olive oil, maple syrup, ginger, garlic, turmeric, salt, and black pepper in a small bowl. The tahini may thicken at first; continue whisking until smooth. Add more warm water 1 teaspoon at a time if needed. The finished dressing should be creamy and pourable.

Divide the quinoa and massaged kale among four bowls. Add the roasted sweet potato, chickpeas, and broccoli. Arrange the red cabbage, avocado, pomegranate arils, and pumpkin seeds over the top.

Drizzle each bowl with the turmeric tahini dressing. Serve while the roasted ingredients are warm, or let them cool and serve the bowls at room temperature.