Steak and Spinach Rolls

Up your grilling game with this elegant version of steak rolls!

1 1/2 lb. flank steak 

kosher salt

pepper 

1 egg, beaten 

1 (10 oz.) package frozen chopped spinach 

1/3 C. fine dry bread crumbs 

1 T. butter 

1 T.flour 

2 T. Dijon mustard 

1 T. horseradish 

1/2 C. milk 

1/2 C. beef broth 

1 T. fresh snipped chives (dried chives or sliced green onion tops also work well)

1 t. fresh lemon juice

Cook spinach according to package directions; squeeze dry and set aside. Using the coarse-tooth side of a meat mallet, pound the flank steak into a 12" x 8" rectangle, working from the center out. Score one side of the steak, using a sharp knife to make shallow diagonal cuts across the steak in a diamond pattern. Sprinkle with salt and pepper; set aside. For filling, in small bowl combine egg and spinach; stir in bread crumbs. Spread filling over unscored side of steak. Starting at narrow end, roll up steak jelly-roll style; secure with wooden picks at 1" intervals. Cut the roll between picks into 1" thick slices. Grill steak rolls uncovered over medium coals (or setting on gas grill) for 8 minutes; turn and continue to cook until desired doneness, about 8-10 minutes more for medium. Remove from grill and let rest for 10 minutes. While meat is resting, make the sauce. Melt butter in small saucepan. Stir in flour, mustard, and horseradish; add milk and beef broth. Cook and stir until thickened and bubbly; cook 1 minute more. Remove from heat; stir in chives and lemon juice. Remove skewers from meat rolls and spoon sauce over.