Wash brussels sprouts thoroughly, and remove discolored leaves. Cut off stem ends, and slash the bottom of each sprout with a shallow X.
Combine brussels sprouts and water in a medium saucpan; bring water to a boil over medium-high heat. Cover, reduce heat, and simmer 8 minutes or until the brussels sprouts are tender. Drain well, and set aside.
Melt 2 tablespoons butter in a medium saucepan over low heat; add flour, stirring until smooth. Cook for 1 minute, stirring constantly. Gradually add the chicken broth; cook over medium heat, stirring constantly until the mixture is thickened and bubbly. Add the salt and pepper; stir well.
Add the reserved brussels sprouts and pecans; toss gently to coat evenly. Cook just until the brussels sprouts are thoroughly heated. Transfer to a serving bowl, and keep warm.
Melt the remaining 2 tablespoons butter in a small saucepan over medium heat. Add the breadcrumbs, and cook, stirring occasionally, 4 minutes or until golden brown. Sprinkle the breadcrumb mixture over brussels sprouts.