2 cups chicken broth 4 tablespoons butter 1 onion, finely chopped 2 cups arborio rice 1 1/4 cups drained chopped canned artichoke hearts Grated peel of 1 lemon plus 2 teaspoons lemon juice Salt and pepper 2/3 cup grated parmesan cheese 1/3 cup chopped flat-leaf parsley 1/3 cup walnuts, toasted and chopped In a saucepan, bring the broth and 4 cups water to a boil, cover and keep at a simmer. In a large saucepan, melt 2 tablespoons butter over medium heat. Add the onion and cook, stirring, until softened, about 5 minutes. Add the rice and stir until lightly toasted, about 2 minutes. Stir in 1 cup of the broth mixture, bring to a simmer and cook, stirring, until the liquid is absorbed, 2 to 3 minutes. Maintaining a low simmer, continue to add the broth mixture, 1/2 cup at a time, stirring frequently and allowing the rice to absorb the liquid. Cook until the rice is tender, about 20 minutes. In the last...