The hearty fungi and chopped walnuts take the place of traditional meat.
Photography by Robert Bredvad
In the bowl of a food processor and working in batches, pulse the mushrooms until finely chopped. Transfer to a large bowl. Repeat this process separately with the walnuts, carrots, onion, and garlic.
In a large enameled cast-iron dish, heat the olive oil. Add the fennel seeds and crushed red pepper and toast over moderate heat until fragrant, about 30 seconds. Add the chopped mushrooms, walnuts, carrots, onion, and garlic, season with salt and pepper and cook until tender, about 15 minutes. Push the vegetables to the sides and make a well in the center; add the tomato paste. Cook over moderate heat until the tomato paste is deep red, about one minute. Fold the tomato paste into the vegetables. Add the broth, scraping up any brown bits on the bottom of the pan.
In a medium bowl, whisk the crushed tomatoes with the reishi powder until smooth, then add to the dish. Add the parmesan rind and rosemary sprig and season with salt and pepper. Reduce the heat to low, cover partially and simmer the sauce, stirring occasionally, until thickened, about 20 minutes. Discard the rind and rosemary sprig.
Meanwhile, bring a large pot of water to a boil, then season generously with salt. Cook the butternut squash noodles until just tender, about two minutes then drain.
Transfer the squash noodles to four bowls and top with the bolognese. Garnish with the shaved parmesan and drizzle with olive oil.