Preparation

• Put a large pot of salted water on to boil over high heat. Heat the butter and olive oil in a 12-inch skillet over moderately low heat. Add the onion and cook until softened, about 10 min. Meanwhile, cut each artichoke half into very thin wedges (about 8 per half). Return the wedges to the lemon water. When the onion is soft, drain the artichokes and add them to the skillet. Season with salt and pepper; stir to coat. Cover and reduce the heat to low. Cook until the artichokes are tender, 20 to 30 min. Check occasionally to be sure they’re not burning or sticking; adjust the heat accordingly and add a tablespoon or two of water if necessary to prevent burning. Add the broth, cream, hazelnuts, and 2 Tbs. parsley to the skillet, and bring to a simmer over medium-high heat. Simmer until thickened slightly, 8 to 10 minutes. Taste and adjust the seasonings.
• While the sauce is reducing, cook the pasta in the boiling water until al dente. Set aside 1 cup of the pasta water, drain the pasta, and return it to the warm pot. Add the sauce to the pasta and toss well. If the sauce is too thin, return the pot to medium heat and cook until the pasta absorbs most of it. If the pasta seems dry, moisten with some of the reserved water. Serve immediately in warm bowls, garnishing each portion with a little more parsley.