Kamut is an ancient grain that's twice as big as wheat and boasts a buttery flavor and toothsome bite. It's the perfect partner for coriander-roasted squash and carrots.
Make the toasted spiced pepitas: Preheat oven to 350 degrees. In a small bowl, toss to combine pumpkin seeds and oil. Spread seeds out evenly on a small rimmed baking sheet and bake until golden and crisp, about 15 minutes. Transfer toasted seeds to a small bowl, add coriander, and toss to combine. Season with salt and pepper; set aside.
Make the kamut: Soak kamut in water for 8 hours or up to overnight. Drain and place in a medium saucepan with a tight-fitting lid. Add stock and bring to a boil. Cover, reduce heat to low, and simmer until kamut is tender, about 40 minutes. Remove from heat and drain.
Preheat oven to 425 degrees. Place squash, carrots, shallots, 2 tablespoons oil, and 2 teaspoons coriander seeds in a large bowl. Season with salt and pepper and toss to combine. Spread vegetables in one layer on a large parchment-lined rimmed baking sheet. Transfer to oven and roast until vegetables are golden brown and tender, 25 to 30 minutes. Transfer to a large bowl along with kamut.
In a large bowl, whisk together vinegar, lemon zest and juice, and remaining 3 tablespoons oil and 2 tablespoons coriander seeds; season with salt and pepper. Add vegetable-and-kamut mixture and gently toss to combine. Stir in watercress, transfer to a large serving platter, and sprinkle with reserved pepitas.