Slow cooker flank steak and gravy with mushrooms is killer! The best Crockpot beef for dinner that’s high in protein and full of flavor. If you loved our air fryer flank steak you’re going to love this one smothered in a thick sauce.

Slow Cooker Flank Steak
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This slow cooker flank steak with mushroom gravy 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. (affiliate links present)

How to Cook Flank Steak in Crockpot

Seriously, beef in a slow cooker 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 pulled beef you’ll love.

Let’s talk a little bit about slow cooking shall we?? First off I have a few different varieties and I love them all. Each one has an occasion to be used like….

  1. This is my favorite 6 quart programmable one with a locking lid so it’s great for bringing to a potluck too.
  2. I prefer not to use liners, but rather just spray olive oil inside before adding my food for easier cleanups.

Let me give you a peek of my pretty thang I bought recently. It goes with my kitchen so I can just leave it out on the countertop all the time. ๐Ÿ˜‰

A floral design slow cooker with a white base and lid sits on a kitchen countertop, perfect for whipping up a 5 ingredient crockpot chili recipe.

Slow Cooker Flank Steak

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.

How long does flank steak take to 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.

What is the best beef to use in a slow cooker?

This one is great but 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.

Flank Steak in Crockpot

Flank Steak in Slow Cooker

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.

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.

  • 1.5-2 lb flank steak was used here, that will feed 4-6
  • Olive oil
  • Minced roasted garlic
  • Some beef broth
  • I package of sliced mushrooms
  • 1 onion of your choice, or a mixture of a few types
  • A given is salt and pepper
  • Butter
  • Thyme
  • A bit of cayenne won’t make it spicy but add a little kick into the mix
  • You’ll want some cornstarch to thicken the sauce at the end

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.

Flank Steak in Slow Cooker

How to Slow Cook Flank Steak

You can print recipe at the bottom of this post for you to read. Here is a quick step by step to look at before you get everything out;

  • Slice your onions, set aside. Spread the olive oil onto your cut of meat. 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 edges.
    • Break up butter and place around mushrooms. Pour beef broth over steak.
  • Cover and cook in Crock pot for 8-10 hours cooking time on low. When the steak is fully cooked, place the steak, mushrooms, and onions on a dish. Set aside.
    • Remove about half cup of liquid from the pot and pour into a small bowl.
      • Whisk together cornstarch and liquid, along with a dash of cayenne pepper (if desired).
  • Pour in to create a thicker gravy. Place cuts of beef, mushrooms, and onions back into slow cooker to soak it on up.

Shred or slice the meat and serve over garlic mashed potatoes for the ultimate comfort food.

Slow Cooker Flank Steak

Slow Cooker Steak and Gravy

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.

Should I sear flank steak before putting it in the Crock pot?

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.

How many hours do you cook flank steak in slow cooker on high?

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.

How to Slow Cook Flank Steak
How to Slow Cook Flank Steak
5 from 3 votes

Slow Cooker Flank Steak

By The Typical Mom
Slow cooker flank steak and gravy with mushrooms is killer! The best Crockpot beef for dinner that's high in protein and full of flavor.
Prep: 10 minutes
Cook: 8 hours
Servings: 8
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Equipment

  • 1 slow cooker

Ingredients 

  • 1.5-2 lb flank steak
  • 1 tbsp olive oil
  • 2 tbsp minced garlic
  • 1 c 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, 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

Serving: 2oz, Calories: 173kcal, Carbohydrates: 3g, Protein: 20g, Fat: 9g, Saturated Fat: 4g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 4g, Trans Fat: 1g, Cholesterol: 59mg, Sodium: 399mg, Potassium: 428mg, Fiber: 1g, Sugar: 1g, Vitamin A: 214IU, Vitamin C: 3mg, Calcium: 28mg, Iron: 2mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Additional Info

Course: Entree, Main Course
Cuisine: American
Tried this recipe?Mention @thetypical_mom or tag #thetypicalmom!
How to Slow Cook Flank Steak

About The Typical Mom

Justine is the creative mind behind The Typical Mom and The Typical Family on YouTube. She began blogging about easy recipes, budget friendly activities for kids, and fun family travel destinations in September 2012.

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12 Comments

  1. Made it for a large group, rave reviews, more or less to recipe, added Gochujang, dry rub, marinated jalapeรฑos (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!

  2. 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!

  3. 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

  4. Could this be made in
    the Ninja pressure cooker? Thoughts on how long to cook and any changes needed?