How to Make It
Heat a cast-iron skillet until smoking, 3 minutes. Add the yellow onion cut side down and cook over high heat, without turning, until completely charred, 5 minutes. Transfer the onion halves to a plate.
In a large saucepan, heat 1 tablespoon of the olive oil. Add the reserved squash skins and seeds and cook over moderate heat, stirring occasionally, until lightly browned, about 5 minutes. Add the broth, charred onion, tomatoes, ginger, cloves, cinnamon stick and 2 teaspoons of salt and bring to a simmer over moderately high heat. Reduce the heat to low and cook until the broth is a deep golden brown, about 1 hour. Strain the squash broth and return it to the saucepan; keep warm.
Meanwhile, preheat the oven to 400°. On a rimmed baking sheet, toss the fideos with 1 teaspoon of the olive oil. Toast in the oven until golden, about 4 minutes. Transfer to a bowl.
On the rimmed baking sheet, toss the squash cubes with the remaining 1 tablespoon of olive oil and season with salt and pepper. Roast the squash until beginning to brown but still slightly firm, about 12 minutes.
Bring the broth to a simmer. Add the kale and pearl onions and cook over moderately high heat until the onions start to soften, 5 minutes. Add the squash and fideos and cook until the fideos are al dente, 8 minutes longer. Season with salt and pepper and serve.