Leftover Steak Soup
You can make this easy low carb soup recipe in no time at all! Use leftover steak if you have it, or cook up some fresh sirloin. You will not regret it!

I initially intended this Steak Soup Recipe to use fresh top sirloin steak…and you can definitely do that! But, sometimes we have leftover steak that we need new and exciting recipes for (first world problem, right?)
This leftover steak soup recipe is packed with flavor…even my picky husband loved it!
SOME OTHER LEFTOVER STEAK IDEAS
- Add it to a salad
- Omelette
- Beef stroganoff
- Steak fried rice (use cauliflower rice for low carb)
HOW TO MAKE STEAK SOUP
To get started with the soup, we first must have leftover steak or some steak hanging out in the fridge. If you have steak already cooked, cut it into 1 inch cubes and move on to the next step. For fresh steak, cut it into 1 inch cubes and sear it on all sides in a hot dutch oven or heavy bottom pot. I did mine in batches.

After all of the steak has been browned, remove it from the pot and set it aside. Then we add in the diced onion and let it caramelize. Now it is time for the minced garlic, dried herbs, and the sliced mushrooms.

We want to get them softened and browned so they look like this:

Then we add in the beef broth and the soup is almost finished! After the broth, I like to add in a thickener. My preference is Xanthan gum because it only requires a teaspoon and it is low carb friendly. You could also make a slurry. After I add the xanthin gum, I bring the soup to a boil so it will start to thicken.
Now it’s time for the steak! Tun off the heat and add in the steak, then ladle into bowls and serve.

Some other low carb soup recipes you will find here are:
- Cream of Cauliflower Soup
- Low Carb Zuppa Tuscana
- Curried Pumpkin Soup
- Instant Pot Chicken Soup
- Keto Tomato Soup
Leftover Steak Soup

Ingredients
- 2 Pounds Top Sirloin Steak, Raw or already cooked
- Kosher salt
- 2 Tablespoons Butter
- 2 Tablespoons Olive oil
- 1/2 Onion, diced
- 4 Cloves Garlic, minced
- 1 teaspoon Italian seasoning
- 1 teaspoon Dried parsley
- 1/2 teaspoon dried thyme
- 1 Pound Mushrooms, sliced
- 4 Cups Beef broth
- 1 teaspoon xanthan gum (you can also make a slurry)
Instructions
- If you using already cooked steak, cut into 1 inch cubes and set aside. In a heavy bottom pot over medium heat, add the butter and olive oil. Continue to 3rd step.
- For fresh steak: In a heavy bottom pot over medium high heat, add the butter and olive oil. Cut the fresh steak into 1 inch cubes and season with salt. Sear all sides and then remove from the pot. work in batches so you do not overcrowd the pot. Set cooked steak aside.
- In the same pot over medium heat, add the diced onion. Cook until the onion is browned and softened. Now add in the garlic, herbs, and mushrooms. Continue to cook until the mushrooms are browned and soft.
- Add in the beef broth and the xanthan gum. Bring the soup to a boil and cook for a few minutes to let it thicken.
- Add in the steak and cook for a few minutes to heat through. Ladle into bowls and serve.
Notes
Nutrition

Added a few flavor amplifiers. Burgundy,Rosemary-Lemon Salt, and juiced half a ĺemon into it right before serving. Nothing but complements.
I toasted a piece of zero carb bread and put it and a slice of provolone cheese on top and broiled. Did not add any carbs an reminded me of a hearty French onion soup. Yum
Absolutely wonderful! I did get the recipe mixed up with another one and used Worcestershire sauce, but it still came out amazing and my husband who is extremely picky about soups loved it too! My 16yr old daughter thought it was amazing. Thank you so much!
It looks good, but 2 pounds of steak is not “leftover”. Looking for something with maybe a small 8 oz steak, something to flavor and give just a bit of beef.
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I made this exactly to the recipe and it was fantastic! Gluten free for me and low carb for the hubs. ???? Very easy and flavorful. I will definitely make again.
Easy, quick, delicious and a great way to use leftovers when you dont want to keep eating the same thing. Highly recommend! I like it with a dash of worcestershire and crusty bread ????
This is great as-is but is the perfect “throw stuff in” base recipe. I’ll add red wine, peas, carrots, fresh herbs or whatever else needs to get used up.
Very good. Thank you!
Amazing taste thank you had tons of left over ribeye steaks and this just hit the spot
LOL….I never have 2 pounds of leftover steak, but I am going to try this with fresh steak. It is finally starting to feel like fall and soup is on the menu. We have game day for my son, and I wanted to do this in the slow cooker. I was going to saute the meat, onions, and steak prior, using my slow cooker’s saute button. How long would you recommend cooking this on low? Would 7-8 hours be too long? The steak that I am using is a tougher type of meat.
Oh my gosh, Jennifer, I so agree about loving soup! I have some leftover air fryer steak bites. I can’t wait to make this soup tonight. Thanks for the recipe????????
I made this with leftover tri-tip. No additional spices needed, doubled the mushrooms and used frozen homemade chicken broth.
Amazing!!!!
I just made this with left over rib eye. I changed nothing. It is delish! I’m a soup girl too! Loved it
I added 1 cup of small diced potato with the onions. Then baby carrots right before the mushrooms and added tarragon to the spices. . Deglazed the pot with 1/4 cup of red wine. Amazing! Thanks for the recipe!
Could you add potatoes,carrots?
yep!
This soup is amazing! I’ve made it twice.. I absolutely crave it!
Very tasty! I adapted this recipe to what I had, which was leftover cooked steak that was a bit too chewy. I figured stewing it would make it more tender, which it did. The sauteed mushroom and onions went very well with the steak. I also added some chopped carrot and zucchini to mine for extra veggies. Since both the bouillion cube and the steak had a lot of seasoning and spices, I didn’t add any others. Was delicious, thanks!
I didn’t have nearly as much leftover steak as you did, but I used the amounts in your recipe for all the other ingredients and it was still fantastic. AND – I was using venison steak. 🙂
I love this recipe with venison too, it’s the perfect base, and cooking from raw only takes a few minutes, plus can add whatever tastes good or follow the recipe!
Perfect! I’ve been looking for a recipe to use up left over rib roast from our Christmas dinner – and to use the beef left on the bones too! Can’t wait to try it!
So yummy! Have a pot in the stove now, waiting for hubby to get home. Hope I can wait that long!
Love the suggestions from your readers. I am going to be swapping out the mushrooms.
The flavor was so rich and delicious . I love mushrooms with steak and tried it in the soup together for the first time!
I’ve made this twice and it’s delicious!! Even better the next day. The flavors are great!
So glad to hear that!
Any other options instead of the mushrooms?
Cauliflower rice, diced eggplant, zucchini, or you could just add extra onion.
I just got a KILLER deal of steak after the new year! I am making this tonight!
This soup is hearty and flavorful. I’m thrilled to have found this recipe. I’ll be making it often this winter!