For a meal with all the tenderness of fillet steak but without the price tag, I can thoroughly recommend this slow cooker flat iron steak recipe. What's more, the cooking juices can be transformed into the most incredible sauce.
Flat-iron steak is a relatively new cut of meat that is rapidly becoming more and more popular as people discover just how tender it can be. The price is relatively low compared to other cuts of steak and if I were marketing this meat (which I'm not), I think I would change the name to Poor Man's Fillet!
It is a cut of beef from the shoulder of the cow, specifically the top blade muscle, otherwise known as the chuck. Flat iron steak is the result of separating this muscle into two pieces along the tough layer of collagen that runs through it. The result is a tender piece of meat, flat in shape and perfectly marbled, making it ideal for a long, slow cooking process.
For this recipe, I cooked the flat iron steak in a slow cooker with onions, mushrooms and a small amount of well-seasoned stock. Once cooked, I removed the meat to a plate and thickened the stock with cream and a mixture of cornflour and water before pouring it over the steak.
Because the sauce is rich and creamy, I chose to serve the steak with plain boiled potatoes and broccoli.
The result was the most tender and flavourful steak I have ever eaten. It's certainly not a 'chewy' meat, it has more of a soft melt-in-the-mouth texture. Combined with the creamy mushroom and onion sauce it was a meal fit for a king.
What you will need
Equipment
The main piece of equipment is a slow cooker. Unfortunately my slow-cooker doesn't have a timer, meaning I have to keep an eye on the clock. When it needs replacing, I'll probably go for one with a timer.
You will also need and sharp knife and a chopping board for cutting up the mushrooms and onions, a saucepan for making the sauce and a frying pan for searing the steak.
Ingredients
This recipe will feed 2 people, but you will probably have some sauce left over. However, you can freeze the sauce and add it to your next stew or casserole, or simply warm it up and serve over a chicken schnitzel.
If you want to make enough to feed 4 people then simply double the amount of meat. The sauce will be sufficient for 4!
- Flat iron steak - in the UK, I get my flat iron steak from Morrisons, where I have also seen it labelled as Denver steak (don't ask me why). I live in a relatively small town, so you should easily find it in the larger towns. You can also ask your butcher to cut it for you. Ask him to separate the flat piece from a top blade roast.
- Mushrooms - I used normal white cap mushrooms but you could use whatever you have available - chestnuts, baby mushrooms or portobello mushrooms would all work. The mushrooms should be thickly sliced.
- Onions - these should be peeled and thinly sliced.
- Beef stock pot - this is for the stock. I just dissolve it in a cup of boiling water. You could use an Oxo cube instead, or even liquid beef stock if you have it.
- Tomato puree or tomato paste - this is made with highly concentrated tomatoes, normally sold in a tube or a jar.
- Worcestershire sauce - you could substitute this with Henderson's relish, or even dark soy sauce.
- Double cream (not pictured) - this is optional, but I like to stir about half a cup of cream into the gravy once it's been thickened.
- You will also need these additional ingredients:
- sunflower or other neutral-flavoured oil for browning the steak
- salt for seasoning (optional)
- cornflour or cornstarch for thickening the gravy
- chopped parsley for garnish (optional)
**You can get the exact quantities of all the ingredients on the printable recipe card at the end of this post**
Instructions
Slice the onions and mushrooms and arrange them on the bottom of your slow cooker.
Season the steak lightly with salt (optional) and heat one or two tablespoons of oil in a frying pan. When the oil is hot, sear the steak for 60 to 90 seconds per side, until lightly browned.
Arrange the steak on top of the onions and mushrooms.
Combine the Worcestershire sauce and tomato puree with the stock and pour it over the meat and vegetables in the slow cooker. Cook on low for 6 to 7 hours until the onions are softened and the meat is tender.
Top tip - when adding the liquid to the slow cooker, it should just cover the mushrooms and onions and the steak should rest on top. The vegetables will release moisture as they cook and the steak will sink down into the liquid.
Carefully remove the meat from the slow cooker, arrange it on a serving plate and keep it warm while you thicken the gravy. Take care - the meat will be very soft and inclined to fall apart.
Pour the stock, mushrooms and onions into a small saucepan.
To thicken the gravy mix 2 tablespoons of cornflour with a splash of water to a smooth paste. Stir it into the sauce over a moderate heat until the sauce thickens.
Once the sauce is the consistency of thick gravy, stir in the cream.
Pour the sauce over the meat and optionally garnish with chopped parsley. Serve hot with your choice of vegetables.
Storage
I haven't tried to freeze the cooked meat so I'm afraid I don't know how well it will stand up to freezing and being defrosted.
You can freeze the raw meat (from the supermarket or butcher) for up to 4 months. I normally buy 2 or 3 packets at a time, use one and freeze the others.
The sauce can be frozen in a suitable freezer container for up to 3 months. To use it, let it defrost and then reheat it in a saucepan until piping hot.
FAQ
It is the shape of the meat that gives flat iron steak its name. The flat cut resembles an old-fashioned flat iron, the kind that was once used for pressing clothes!
Flat iron steak can also be grilled or pan-fried.
Yes, you can add other vegetables such as potatoes and carrots to make this a complete meal in one dish. Just remove the additional vegetables to a serving dish before tipping the mushrooms and onions into a saucepan to make the gravy.
Save for later
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Related recipes
If you enjoyed this slow cooker flat iron steak recipe you may like to try some of my other slow cooker meals:
You can find all of these plus similar recipes on my slow-cooker recipes page.
Pairing
You may like to serve this flat iron steak with one or more of these vegetable sides:
📋The recipe
Slow cooker flat iron steak
(Click the stars to rate this recipe)
Equipment
- Slow cooker
- Sharp Knife
- Chopping Board
- Frying Pan
- Saucepan
Ingredients
- 12 ounces / 350 grams flat iron steak
- 8 ounces / 225 grams sliced white mushrooms
- 1 medium onion thinly sliced
- 1 beef stock pot dissolved in 1 cup boiling water
- 1 tablespoon tomato puree or tomato paste
- 2 tablespoons Worcestershire sauce
- ½ cup / 120 ml double or heavy cream
- 1 to 2 tablespoons sunflower oil
- ½ teaspoon salt optional
- 2 tablespoons cornflour or cornstarch or more as needed
- 1 to 2 tablespoons finely chopped parsley optional (for garnish)
Instructions
- Slice the onions and mushrooms and arrange them on the bottom of your slow cooker.8 ounces / 225 grams sliced white mushrooms, 1 medium onion
- Season the steak lightly with salt (optional) and heat one or two tablespoons of oil in a frying pan. When the oil is hot, sear the steak for 60 to 90 seconds per side, until lightly browned.1 to 2 tablespoons sunflower oil, ½ teaspoon salt, 12 ounces / 350 grams flat iron steak
- Arrange the steak on top of the onions and mushrooms.
- Combine the Worcestershire sauce and tomato puree with the stock and pour it over the meat and vegetables in the slow cooker. Cook on low for 6 to 7 hours until the onions are softened and the meat is tender.1 tablespoon tomato puree or tomato paste, 2 tablespoons Worcestershire sauce, 1 beef stock pot dissolved in 1 cup boiling water
- Carefully remove the meat from the slow cooker, arrange it on a serving plate and keep it warm while you thicken the gravy. Take care - the meat will be very soft and inclined to fall apart.
- Pour the stock, mushrooms and onions into a small saucepan.
- To thicken the gravy mix 2 tablespoons of cornflour with a splash of water to a smooth paste. Stir it into the sauce over a moderate heat until the sauce thickens.2 tablespoons cornflour or cornstarch
- Once the sauce is the consistency of thick gravy, stir in the cream.½ cup / 120 ml double or heavy cream
- Pour the sauce over the meat and optionally garnish with chopped parsley. Serve hot with your choice of vegetables.1 to 2 tablespoons finely chopped parsley
Notes
- I haven't tried to freeze the cooked meat so I'm afraid I don't know how well it will stand up to freezing and being defrosted.
- You can freeze the raw meat (from the supermarket or butcher) for up to 4 months. I normally buy 2 or 3 packets at a time, use one and freeze the others.
- The sauce can be frozen in a suitable freezer container for up to 3 months. To use it, let it defrost and then reheat it in a saucepan until piping hot.
Nutrition
I am not a nutritionist. The nutrition information has been calculated using an on-line calculator, and is intended for information and guidance purposes only. If the nutrition information is important to you, you should consider calculating it yourself, using your preferred tool.
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