Slow cooker flank steak and gravy with mushrooms is killer! The best high protein dinner that melts in your mouth when done. If you loved our air fryer flank steak you’re going to love this one smothered in a thick sauce.

This meal is amazing. I love working my way thru my easy Crockpot recipes during the summertime so I can make dinner without a lot of effort and not heat up the house. If you’re like us this is going to become a new fave.
Flank steak in Crockpot is the way to go. Makes fresh and even Crockpot frozen roast pieces of thick proteins fork tender and delicious with little to no prep work. Smothering them with a thick flavorful gravy is a must if you ask my family. Takes us back to our childhood because that’s just the way our grandmothers cooked.
Throw in some mushrooms and onions are always a cheap way to bring yum and texture to any dish. You can literally throw it all in when you get up in the morning and when everyone is finally home and hangry it’s ready and falling apart. Don’t expect to slice this, it’s too tender for that, it’s more like the most incredible Crockpot pulled beef you’ll love.
Ingredient Notes
1.5-2 lb flank steak was used here, that will feed 4-6 in general depending on your family’s needs. For the 5 of us it is plenty with a meal left over to save for the next day too (bonus).
You will want a bit of olive oil for this. If you don’t have that or want an alternative I prefer avocado oil over the rest for it’s flavor and health benefits.
Minced air fryer garlic is what I prefer to use for the richness and added flavor. If I don’t have time to prep this beforehand I will just grab some right out of the jar and go with that.
You need liquid for this too of course, let’s discuss this. Water works, but beef broth is by far my preference. Reason why you should use broth is the added flavor and salt it offers. Really any variations work but since this is beef, I go with this option.
For veggies and to make it sort of like a healthier stroganoff of sorts I will add a package of sliced mushrooms. If you want them to stay more firm go with baby bellas, aka portabellas. Button or white work too but will get rather soft.
Slice a white or yellow onion of your choice, or a mixture of a few types works as well. A cheap way to add texture and flavor to the dish.
Butter I use is Kerrigold salted, my fave. You could opt for a dairy free vegan alternative if need be and it won’t change much of anything.
You’ll want some cornstarch to thicken the sauce, gravy, at the end unless you are just using the liquid to cook and not to serve with.
Just layer the meat and vegetables and then pour in your liquid. You can whisk to thicken right in the pot at the end or use a small saucepan to boil it. Shred or slice the meat and serve over garlic mashed potatoes for the ultimate comfort food.
This is all about the sauce y’all. If you want to go the lazy route you can use a Campbells slow cooker sauce that comes packaged and ready to jump dump right in. Of course homemade is always best so if you want to make our mushroom gravy the ingredients below are necessary. Onion gravy is pretty killer too if you’d rather go that route.
I will say that a thick gravy is a must to serve together. It adds flavor and moisture to the entire dish. Make a bit spicy if you would like, make homemade or use a ready made jar.
Does flank steak get more tender the longer you cook it?
Yep, basically. That means if you get back an hour after you thought you would it won’t be ruined. It actually might be better than you initially thought it would be. Like I said, just don’t have the expectation that you’ll be able to get a nice pretty slice out of it. If you have my machine like you see above you can set it and forget the timing too.
This is different than if you used a T bone, NY Strip or Porterhouse “regular” type and made Crockpot steak and potatoes. You would want that to be a bit more on the medium rare side.
Slow Cooker Flank Steak Recipe
Equipment
- 1 slow cooker
Ingredients
- 1.5-2 lb flank steak
- 1 tbsp olive oil
- 2 tbsp minced garlic
- 1 cup beef broth
- 8 oz mushrooms
- 1 onion
- 3/4 tsp salt
- 3/4 tsp pepper
- 2 tbsp butter
- 1/2 tbsp thyme
- 1 tsp cayenne
- 2 tbsp cornstarch, to thicken gravy
Instructions
- Thinly slice onions, set aside. Spread the olive oil onto the flank steak. Sprinkle on minced garlic, salt, pepper, and thyme on top. Slice mushrooms, set aside.
- Place flank steak in slow cooker and spread mushrooms and onions around the edge of the steak. Break up butter and place around mushrooms. Pour beef broth over steak.
- Cook for 8-10 hours on low. When the steak is fully cooked, place the steak, mushrooms, and onions on a dish. Set aside. Remove 1⁄2 cup liquid from the slow cooker and pour into a small bowl. Whisk together cornstarch and liquid, along with a dash of cayenne pepper (if desired).
- Whisk into slow cooker to create gravy. Repeat if needed for a thicker gravy. Place steak, mushrooms, and onions back into slow cooker if desired or pour gravy onto dish with the steak.
Video
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
How long does flank steak take to slow cook?
About 8 hours give or take, depending on how thick yours is. If you can set it to this timing your machine will automatically turn itself from cook to keep warm at the end of the day. That way it won’t be cold when its dinnertime but won’t fall apart quite as much.
Can you use hanger steak instead of flank?
Yes, that is the best substitute, and that cut is actually a bit more tender. Both will cook similarly with the same cook time and this sauce goes with either one. In both cases there is a need for low heat for a long time to break it down.
Some prefer to just squeeze lime juice on top and serve inside of some tacos. Others smother it with the brown gravy on top of taters. Juicy and tender this will surely become one of your favorite steak recipes of all time.
Ready? Already made it, thought it was amazing and looking for what you should try out next? I would suggest our slow cooker carne asada recipe that can use this same cut or skirt steak. Both are on the less expensive side but slightly different. Skirt is typically tougher and cooked for less time to get to be tender. Give both a whirl and see which cut you prefer.
FAQ
I have made it both ways. Searing beef will lock in the juices, that is the main reason why you do it. If you forget or don’t have time to do this step it won’t ruin your dish. You can put it right in with onions and our gravy mixture and slow cook to perfectly melt in your mouth texture as is.
I would not recommend this, period. The whole point of using a sloooooooow cooker is to use the low heat function so it cooks for a really long time to break down the connective tissues over time. This is what makes it tender and easily shredded.
We have cooked Crockpot chuck roast quite a bit too. That one works maybe a bit better only because it is marbled with some added fat that adds to the overall flavor. Flank is quite lean so you do need to make sure to keep it nice and moist the entire time it is being heated or it will dry out for sure.
I don’t have any onions or mushrooms can I make this without them and it still be tasty?
Sure, just less texture basically
Made it for a large group, rave reviews, more or less to recipe, added Gochujang, dry rub, marinated jalapeños (plus extra marinade from can for more spice) & maple syrup :-0. Will add more mushrooms and onions next time. MMMM thank you for the recipe Typical Mom!
Yay so glad it was a hit for y’all!!
I followed your instructions to the letter because I’m not always that great at new recipes but it turned out great and it’s now a family favorite. Thank you!
OH good!!
Yes! This is the best recipe! I add about a tbsp of red wine vinegar to the mix and honestly, it’s a pot licker!! Thanks you
OOhhhh great add
Can this be cooked on high for 4-5 hours? Thanks!
I don’t like using high ever, I think it dries out the meat
Could this be made in
the Ninja pressure cooker? Thoughts on how long to cook and any changes needed?
You could use our air fryer flank steak recipe and use the drippings in the bottom to make a gravy with it. https://temeculablogs.com/air-fryer-flank-steak/