Meanwhile, combine butter, blue cheese, and chives a small bowl; stir using a wooden spoon until blended. Cover and chill.
Place a large nonstick skillet over medium-high heat until hot. Pat fillets dry with paper towels, and coat both sides with cooking spray.
Add fillets to pan; cook 3 to 4 minutes on each side or until desired degree of doneness. For grown-up servings, top 2 fillets with 1 Tbsp. each of Blue Cheese Butter. For plain servings, serve fillets without Blue Cheese Butter.
Leftover Note: Christine H., of Danville, CA, suggests spooning the leftover Blue Cheese Butter into 1 Tbsp. portions in a single layer on a large plate. Freeze until firm; then transfer to an airtight container, and freeze up to 1 month. Use the butter again to prepare this recipe or to season your favorite steamed vegetables.
MENU IDEA FOR 4 * Beef Fillets with Blue Cheese Butter * Steamed asparagus * Crusty French rolls