Grilled Flank Steak Sandwiches

Flank steak is delicious when marinated and cook on the grill.
These sandwiches are cooked entirely on the grill,
so they have a wonderful smoky flavor.
Ciabatta bread is a flat Italian bread,
very chewy, with a wonderful crust and large holes.
It's perfect for this sandwich because the bread
soaks up the steak juices without getting soggy.

Ingredients:
1 pound flank steak
2 Tbsp. olive oil
1 Tbsp. apple cider vinegar
1/8 tsp. celery seed
1/8 tsp. dry mustard
1/8 tsp. smoked paprika
1/4 tsp. salt
1/8 tsp. pepper
4 (5 inch) chunks ciabatta bread, cut in half lengthwise
8 slices Muenster cheese
1 avocado, thinly sliced

Directions:
Place flank steak in large zip lock bag.
Pour remaining ingredients except bread,
cheese, and avocado into bag.
Seal bag and squish to mix marinade and coat steak.
Refrigerate steak for 1-24 hours.
When ready to eat, prepare and preheat grill.
Place flank steak on grill and cook over medium coals
for 4-5 minutes per side, turning once, until desired doneness.
Set steak aside, covered with foil, for 6 minutes.
While steak is resting, place cheese on all of bread slices
and place on grill, cheese side up, until cheese melts.
Slice flank steak thinly across grain and make sandwiches with cheesy bread and sliced avocado. You can place the sandwiches back on the grill, cover, and toast for 1-2 minutes to finish the sandwiches,
then slice in half and serve immediately.