Preheat oven to 325°F. Press seasoned pepper evenly onto all surfaces of beef roast.
Place roast, fat-side up, on rack in shallow roasting pan. Insert ovenproof meat thermometer so tip is centered in thickest part of beef. Do not add water or cover. Roast in 325°F oven 60 to 75 minutes for medium rare to medium doneness.
Meanwhile, combine cheese, butter and green onion in small bowl until well blended; set aside.
Spray large nonstick skillet with nonstick cooking spray; add Broccolini, onion and water. Cover and cook over medium-high heat 3 minutes. Remove cover and continue cooking 2 to 4 minutes or until water has evaporated and Broccolini is crisp-tender and lightly browned, stirring frequently. Remove from heat. Immediately add 2 tablespoons blue cheese mixture; stir until butter is melted. Season with salt and ground black pepper, as desired. Keep warm.
Remove roast when meat thermometer registers 135°F for medium rare; 150°F for medium. Transfer roast to carving board; tent loosely with aluminum foil. Let stand 10 minutes. (Temperature will continue to rise about 10°F to reach 145°F for medium rare; 160°F for medium.)
Carve roast into slices; season with salt, as desired. Serve with vegetables and remaining blue cheese butter.
Nutrition information per serving: 277 Calories; 144 kcal Calories from fat; 16 g Total Fat; 8 g Saturated Fat; 5 g Monounsaturated Fat; 102 mg Cholesterol; 176 mg Sodium; 7 g Total Carbohydrate; 0.4 g Dietary Fiber; 29 g Protein; 3 mg Iron; 5.8 mg Niacin; 0.6 mg Vitamin B6; 3.4 mcg Vitamin B12; 6.4 mg Zinc; 31.4 mcg Selenium; 4.6 mg Choline;