Melt 4 tablespoons butter in a pot over medium-high heat. Stir in 2 cups converted long-grain rice, 1 teaspoon salt and 1/2 teaspoon pepper. Cook, stirring, until the rice is golden, about 5 minutes. Add 2 cups each chicken broth and water; bring to a simmer, then cover and cook over low heat, 15 minutes. Remove from the heat and let stand 5 minutes. Fluff with a fork and stir in chopped scallions and parsley.