Preheat oven to 325 degrees. Cook onion and celery in margarine in large skillet on medium-high heat until crisp-tender. Add 2 Tbs. of the mustard, the bread cubes, apple and poultry seasoning; mix well. Set aside. Unroll roast. Spread with 2 Tbs. of the remaining mustard; top with the bread mixture. Re-roll roast; secure with kitchen string. Place on rack in roasting pan.

Bake 2 hours or until meat thermometer inserted into thickest part of roast registers 160 degrees.

Remove roast from pan to carving board. Let stand 10 minutes before slicing to serve. Meanwhile, remove 1 Tbs. of the drippings from roasting pan; place in small saucepan. Add flour; stir with wire whisk until well blended. Cook on medium heat 1 minute, stirring constantly. Add apple juice and remaining 1/4 C. mustard; cook and stir until mixture thickens and begins to boil. Remove from heat; stir in parsley. Slice the roast. Serve topped with mustard sauce. Garnish with apple wedges and parsley sprigs just before serving.

Yield: 12 servings