There is something mighty comforting about setting supper to cook low and slow while the weekend carries on around you, and a flat iron steak is a fine choice when you want hearty flavor without a lot of fuss. This sort of simple steak dinner fits right into the Midwestern way of cooking I grew up with, where a handful of pantry staples and a dependable slow cooker could turn an ordinary cut of meat into a tender meal that tastes like you worked all day over the stove.
Serve this slow cooker steak over mashed potatoes, buttered egg noodles, or a scoop of fluffy rice so none of that rich onion gravy goes to waste. A side of green beans, glazed carrots, or simple corn makes it feel like a full Sunday dinner, and a basket of warm rolls is always welcome for sopping up the juices.
Slow Cooker Flat Iron Steak Dinner
Servings: 4 to 6
Ingredients
1 flat iron steak, about 1 1/2 to 2 pounds
1 packet onion soup mix, about 1 ounce
1 cup low-sodium beef broth
1 can cream of mushroom soup, 10 1/2 ounces
1 medium yellow onion, sliced
2 tablespoons Worcestershire sauce
2 tablespoons cornstarch
2 tablespoons cold water
Directions
1. Lay the flat iron steak in the bottom of your slow cooker. Scatter the sliced onion over the top.
2. In a medium bowl, whisk together the onion soup mix, beef broth, cream of mushroom soup, and Worcestershire sauce until smooth. Pour the mixture over the steak and onions.
3. Cover and cook on low for 6 to 8 hours, or until the steak is very tender and easy to slice or shred.
4. Carefully move the steak to a cutting board and keep it warm. In a small bowl, stir the cornstarch and cold water together, then whisk that slurry into the liquid in the slow cooker. Cover and cook on high for 10 to 15 minutes, until the gravy thickens.
5. Slice the steak against the grain or shred it into large pieces, then return it to the slow cooker and spoon the gravy over the top. Serve hot with mashed potatoes, noodles, or rice.
Variations & Tips
Add mushrooms: If your family enjoys mushrooms, add 8 ounces of sliced button mushrooms right into the slow cooker with the onions. They cook down beautifully and make the gravy taste even heartier.
Make it extra oniony: For deeper flavor, let the sliced onions pile up generously over the steak and cook the full 8 hours on low. They nearly melt into the sauce and give it that old-fashioned supper table taste.
Keep the steak tender: Flat iron steak is naturally flavorful, but like most beef it appreciates gentle cooking. Low heat works better than high for the main cook time, and slicing against the grain at the end makes each bite more tender.
Stretch the meal: Leftover steak and gravy can be spooned over toast, tucked into baked potatoes, or served open-faced on sandwich bread the next day. Around my table, that kind of second-day supper never lasts long.