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Guinness Marinated Flat Iron Steak

by | Published Oct 18, 2021 | Last updated Mar 10, 2022 | 0 comments

Prep Time1 hrCook Time10 minsTotal Time1 hr 10 minsYields1 Serving
Flat Iron steak is my go-to cut for a quick and inexpensive dinner. These steaks typically run about 5.99/lb at the grocery store so for around $12 you’ll have a steak that can feed 3-4 people easily. The flat iron is cut from the chuck area of the steer and has a similar texture to sirloin. It’s best cooked on the rare to mid rare side, and as always, slice it across the grain for tender pieces.



Remove flat iron steak from packaging and trim excess silver skin; place the flat iron in a 1-gallon size zip-top bag. Combine the ingredients for the marinade in a small bowl and pour over steak. Marinate for 1 hour.


Prepare charcoal grill for direct grilling at 500 degrees.


Prepare charcoal grill for direct grilling at 500 degrees. While grill is heating prepare Guinness Mushroom sauce: Melt butter in a sauce pan over medium heat. Add shallot and garlic and sauté for 2 minutes. Add sliced mushrooms and season with AP seasoning. Sauté for 2-3 minutes until mushrooms are tender. Add Worcestershire, soy, and balsamic reduce for 3-4 minutes; add Guinness and reduce volume by half (approx 5-7 minutes). Combine corn starch and cold water in a small bowl and whisk into sauce. Allow the mixture to reach a slight boil and remove from heat. Serve warm over steak.


Remove the flat iron steak from the marinade allowing excess moisture to drip back into the zip-top bag. Season the steak with Killer Hogs Steak Rub on all sides.


Place the steak on the grill and cook for 5 minutes. rotate the steak after 2.5 minutes to create grill marks. Repeat the same step for the opposite side for a total cook time of 10 minutes or until the steak reaches 125 internal temperature – medium-rare.


Rest the flat iron for 5-7 minutes before slicing and serve topped with Guinness Mushroom sauce.


 1 flat iron steak, 1.5 lbs
 1 tbsp Killer Hogs Steak Rub
Guinness Flat Iron Steak Marinade
 12 oz Guinness Stout Beer
 2 oz Worcestershire Sauce
 2 oz Soy Sauce
 1 tsp Killer Hogs AP Seasoning
Guinness Mushroom Sauce
 2 tbsp salted butter
 1 small shallot, finely chopped
 5 cloves garlic, minced
 8 oz baby bella mushrooms
 0.50 tsp kosher salt
 0.50 tsp black pepper
 ¼ cup soy sauce
 ¼ cup Worcestershire sauce
 1 tbsp balsamic vinegar
 1 cup Guinness Stout beer
 1 tsp corn starch
 1 tsp cold water


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