Bring a large pot of water to a boil, salt it, add the pasta and cook until al dente. Drain.
While the pasta is working, in a small saucepan, soften the dried mushrooms in the broth over low heat.
In a large nonstick skillet, heat the EVOO, 2 turns of the pan, over medium heat. Add the portobellos, shallots and garlic and cook until tender, 6 minutes. Add the kale, cover the skillet and cook until wilted, about 5 minutes. Season with salt, pepper and the nutmeg and toss.
Using a slotted spoon, transfer the porcinis to a cutting board and chop, then add to the kale mixture. Pour the porcini broth into a bowl or cup, discarding any grit at the bottom of the pan; set aside. Wipe out the pan, add the butter and melt over medium heat. Add the hazelnuts and rosemary and cook for 2 to 3 minutes. Sprinkle the flour on top and cook for 1 minute, then whisk in the reserved porcini broth and cook until thickened, 3 to 4 minutes.
Toss the pasta with the kale mixture and gravy; season with salt and pepper.