1 (3 ounce) package amish seasoning mix
1/2 cup barbecue sauce
1/2 cup chopped onion
1/4 cup chopped celery
1/4 cup chopped green bell pepper
1 teaspoon chopped fresh thyme
1 teaspoon butter or margarine
1 teaspoon Worcestershire sauce
1 teaspoon onion powder
1 teaspoon garlic powder
1 teaspoon Worcestershire sauce
1 teaspoon prepared mustard
1 teaspoon prepared horseradish
1 teaspoon salt
1/2 cup chopped fresh parsley
Heat the oil in a large skillet over medium heat. Saute the onion, celery and green peppers for 5 minutes.
Stir in thyme, butter or margarine, Worcestershire sauce, onion powder, garlic powder, Worcestershire sauce, mustard, horseradish, salt and parsley. Cook over medium heat for 5 minutes, stirring constantly. When the mixture is heated, pour it into the skillet.
Place sirloin or other cut pieces of meat into the skillet. Arrange in a single layer on the bottom of a large baking pan or greased cookie sheet. Cover the pan and refrigerate for 5 to 7 days, allowing the meat to marinate.
While the meat is marinating, layer half of the bread cubes on top of the meat. Cover the bread cubes with remaining bread cubes and refrigerate for at least 4 days. Season with salt, pepper, thyme, butter, Worcestershire sauce, onion powder, garlic powder and horseradish. Cover and refrigerate for at least another 4 days.
While the bread cubes are chilling, gently warm the mustard and horseradish over medium heat. Remove from the fridge and drizzle over the marinade. Cover and refrigerate for at least one hour before serving. Sprinkle with parsley.