Low-Carb Steak and Mushroom Pie is a keto take on the Shepherd’s Pie. This recipe offers up flavorful bites of the best angus beef with mushrooms in a nice thick gravy. It is topped with a cheesy mashed cauliflower making this the perfect comfort food!

To make this recipe you will need: steak, mushrooms, onion, butter, red wine, beef broth, Xanthan gum (for thickening), cauliflower, butter, and cheddar cheese.Low Carb Steak and Mushroom Pie

Disclosure: This post is sponsored by the Certified Angus Beef ® brand in conjunction with a social media campaign through Sunday Supper LLC. All opinions are my own. 

Grumpy loves Shepherd’s pie. I have never been a huge fan, mainly because I didn’t care for mashed potatoes as a topping to my casserole. However, I do love mashed cauliflower! I pretty much love anything with cauliflower in it. So, it was easy to come up with this low carb casserole to please both of us!

Low Carb Steak and Mushroom Pie

I have no cooktop, so I improvised with the Instant Pot for sauteing the beef and mushroom mixture!

If you follow me on Facebook or Instagram, then your likely to know that our kitchen is in renovation. When I first agreed to this post I figured I would have my cooktop installed and working by the time I needed to make it. Well, that didn’t happen! Ugh. Anyways, I had to improvise because I had to make this recipe! While you use the oven to finish this recipe, you can do as I did and use the saute setting on the Instant Pot, or if you don’t have an Instant Pot, go ahead and use your cooktop.

Low Carb Steak and Mushroom Pie

Once you have the cauliflower in the microwave you will want to get started on your beef and mushroom mixture. Put the Instant Pot on the Saute setting. It will automatically give you 30 minutes. This will be more than enough time and you will likely have to cancel to turn off the pot when your done.

Low Carb Steak and Mushroom Pie

Low Carb Steak and Mushroom Pie

Low Carb Steak and Mushroom Pie

How did you thicken the gravy for your steak and mushroom filling?

I used Xanthan Gum. Xanthan Gum is typically used to thicken sauces and also can be used in making breads. I am not experienced enough with keto bread making so I haven’t studied the science of using it in bread yet. However, I can tell you that it works incredibly well as a sauce thickener! If your on the fence about using Xanthan Gum, then go ahead and use arrowroot powder, that is keto friendly where cornstarch is not.

Low Carb Steak and Mushroom Pie

The broth mixture needs to be hot when adding the Xantham Gum and when adding it, you need to lightly sprinkle it over the mixture, then stir it really well to get it to dissolve. After a few more minutes of simmering you will turn the Instant Pot off and let the beef mixture cool down.

How I made the Cauliflower Mash for the Low-Carb Steak and Mushroom Pie!

For the cauliflower, to cook it, I used my microwave. It worked out perfectly! I used riced cauliflower that I had in my fridge, but you can use a small head of cauliflower, chop it up, steam it and go ahead with processing it the same.

Low Carb Steak and Mushroom Pie with Mashed Cauliflower

Low Carb Steak and Mushroom Pie with Mashed Cauliflower

If you have never eaten Mashed Cauliflower in place of potatoes, then you want to definitely give it a try. This was my first time ever doing so and I was completely impressed. It is so delicious, you will hardly believe it is not mashed potatoes! Just look at it! I swear you could fool people if you didn’t tell them! This made the perfect topping to make my Steak and Mushroom Pie low-carb!

Low Carb Steak and Mushroom Pie with Mashed Cauliflower

Once you have both the beef/mushroom mixture and the mashed cauliflower ready, you can assemble your pie. Start with placing the beef mixture in the bottom or your ramekin or casserole pan. Then top with mashed cauliflower and spread it out over the mixture.

Low Carb Steak and Mushroom Pie

The finishing touch is just a little bit more cheese on the topping and bake at 350 for about 25 minutes.

Low-Carb Beef and Mushroom Pie

Low-Carb Steak and Mushroom Pie

Some tips to be sure you get the best casserole results!

  • For this recipe I used a Certified Angus Beef® brand round steak. If you want a steak with more marbling you can use a boneless strip or rib steak.
  • Use the food processor to mix your cauliflower. I promise you, it will turn out far better than if you try to mash it by hand. The food processor will make your mashed cauliflower smooth and creamy. Just like potatoes!
  • Add melted butter grated cheese to your mashed cauliflower to give it that comfort food feel and flavor! Butter is ok on keto and that makes me so very happy!

Be sure to follow Certified Angus Beef® brand on their social channels! Facebook | Twitter | Pinterest | Instagram | LinkedIn | YouTube

PIN IT! Low-Carb Beef and Mushroom Pie – the ultimate keto comfort food!

Low Carb Steak and Mushroom Pie

Low-Carb Steak and Mushroom Pie
Yield: 4 servings

Steak and Mushroom Pie

Prep Time: 20 minutes
Cook Time: 30 minutes
Total Time: 50 minutes

Low-Carb Steak and Mushroom Pie is a keto take on the Shepherd's Pie. This recipe offers up flavorful bites of the best angus beef with mushrooms in a nice thick gravy. It is topped with a cheesy mashed cauliflower making this the perfect comfort food!


For the beef mixture:

  • 3 tablespoons butter
  • 1 lb Certified Angus Beef Steak, cut into cubes (strip or ribeye recommended)
  • 1 lb portobello mushrooms, sliced
  • 1/2 cup diced onion
  • 1/2 dry red wine
  • 1 cup beef broth
  • 1/2 tablespoon Xanthan Gum

For the Mashed Cauliflower

  • 1 tablespoon butter
  • 1 small head cauliflower, about 6 cups
  • 1 tablespoon butter
  • garlic salt to taste
  • 2/3 cup cheddar cheese, divided


You will want to start with getting your cauliflower steamed. Add your cauliflower pieces to your steamer and steam in the microwave for 15 minutes, checking after 10 minutes, until cauliflower is tender. Remove from microwave and set aside.

Using the saute setting on the instant pot, add butter. Swirl it around with your stirring spoon to coat the bottom of the pan. When butter begins to bubble, place onions in instant pot. Cook and stir about 2 minutes. Add mushrooms, garlic salt, and pepper. Stir to combine and saute until mushrooms are cooked, about 7 minutes. Remove from Instant Pot and set aside.

Add another tablespoon of butter to the Instant Pot. When it has melted, add beef and season with salt and pepper. Stir to begin browning. Add 1/2 cup dry red wine to beef and stir, bringing to a simmer. Add beef broth, then Xanthan Gum. Bring back to a simmer, stirring the entire time to incorporate the Xanthan Gum. Remove from heat and set aside.

Using food processor, add cooked cauliflower, butter, salt and pepper and about 1/3 cup of cheddar cheese. Process until smooth.

Divide beef mixture in 4 ramekins or place in 8x8 casserole dish. Top with mashed cauliflower and use a spoon to spread it over the beef mixture. Sprinkle with remaining 1/3 cup of cheese.

Bake in oven at 350 degrees for about 25 minutes. Mixture will be hot, let sit about 10 minutes before consuming.


I always use Certified Angus Beef ® brand. They have set their standards high and the result is the most flavorful, tender, juicy meat you can buy.

Net Carbs: 9

Nutrition information calculated using myfitnesspal is provided as a courtesy, but will vary depending on the specific brands of ingredients you use. Please consult with your doctor regarding specific health needs.

Nutrition Information



Serving Size

1/4 of the recipe

Amount Per Serving Calories 482Total Fat 43gSaturated Fat 26gTrans Fat 0gCholesterol 125mgSodium 565mgCarbohydrates 15gFiber 6gSugar 7gProtein 36g

Did you make this recipe?

Please leave a comment on the blog or share a photo on Instagram