My mother calls them bow-ties and my daughter calls them butterflies, and all three of us concur that this is our favorite pasta shape. Combined with the sensuously bitter combination of artichoke hearts and mustard greens—and the sweetness of slow-cooked onions—the farfalle takes on a distinct character beyond its inspiring shape.

• Step 1 can be done well in advance.
  

1. Heat the olive oil in a very large, deep skillet or a Dutch oven over medium-high heat. When the oil is very hot, add the onion and sauté for 5 minutes.
2. Reduce the heat to medium, add the salt, and sauté for 5 minutes longer. Turn the heat to low, cover, and continue to cook the onions for 20 more minutes. Meanwhile, put up a large potful of water to boil for the pasta.
3. Stir the mustard greens, artichoke hearts, and bouillon into the onions, and heat to a boil. Turn the heat way down, cover, and allow to simmer gently while the pasta cooks.
4. Cook the pasta until it is just tender. Drain well, and transfer to the panful of sauce. Stir well, and cook over low heat for about 5 minutes. Serve hot or warm, topped with freshly ground black pepper and some minced walnuts, if desired.