Smothered flat iron steak in a parmesan pepper sauce

INGREDIENTS
1lb flat iron steak
1⁄2cup zesty Italian dressing, divided
1⁄3cup sour cream
4 1⁄2teaspoons parmesan cheese, grated
3⁄4teaspoon course black pepper
1⁄4teaspoon sea salt
2garlic cloves, chopped
1large onion, thinly sliced

contine
http://ift.tt/2DAXCYZ