How to Make It
Preheat the oven to 375°. Spread the hazelnuts in a pie plate and toast for 12 minutes, until the skins split and the nuts are fragrant. Transfer the nuts to a clean kitchen towel and rub off the skins. Coarsely chop the nuts.
Meanwhile, in a large, deep skillet, cook 4 tablespoons of the unsalted butter over moderate heat until lightly browned, 3 minutes. Add the chanterelles, season with salt and black pepper and cook over high heat, stirring occasionally, until all of the liquid has evaporated and the mushrooms are golden, 8 minutes. Add the shallot, thyme and crushed red pepper and cook over moderately high heat for 5 minutes, stirring. Add the vinegar and cook until evaporated, scraping up any browned bits from the bottom of the skillet. Add the stock and simmer until reduced by half, 10 minutes. Season with salt and black pepper.
In a large pot of salted boiling water, cook the fazzoletti until al dente. Drain and add the pasta to the skillet, along with the remaining 2 tablespoons of butter. Cook over moderate heat, stirring, until the pasta is coated with butter, about 2 minutes. Stir in the chives and serve in shallow bowls, garnishing with the toasted hazelnuts.