Keto Sautéed Butter and Garlic Mushrooms
Published November 8, 2020 • Updated March 11, 2026
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Garlic, butter, lemon, and rosemary in a cast iron skillet. I make this low carb side dish at least twice a week because it goes with literally everything.
I make these keto sauteed mushrooms more than any other side dish on this site. Not because they’re complicated (they’re the opposite), but because they go from raw to golden brown in about 10 minutes and I haven’t found a single protein they don’t pair with.
The biggest thing I’ve learned making these over the years is that butter timing matters. I used to toss everything into the pan at once, butter included, and the butter would burn before the mushrooms even started browning. Now I start with just a touch of olive oil, get the mushrooms going, and add the butter toward the end so it coats everything in that rich, nutty flavor without scorching. The lemon juice goes in after the initial browning too. If you add acid too early, it slows down the browning process, and you end up with pale, steamed mushrooms instead of the deep golden color you want.
I use a cast iron skillet every time. Cast iron holds heat better than stainless steel, which means the mushrooms sear instead of releasing all their water and stewing. That’s the real secret to getting them crispy on the edges. If your mushrooms always turn out soft and watery, the pan temperature is almost certainly the problem.
The rosemary goes in at the very end, just 30 seconds, because fresh rosemary burns fast. I’ve ruined a batch by adding it too early and ending up with bitter, charred herb bits. Garlic gets the same treatment. Thirty seconds of heat is all they need to release their flavor without going acrid.
These are my go-to keto side when I’m making steak, but I pile them onto burgers with keto hamburger buns, toss them into cauliflower fried rice, or serve them alongside oven roasted asparagus and a simple protein. They round out any plate. I also love them next to maple mustard green beans when I want a low carb veggie spread for dinner.
One thing that surprises people: 4 cups of raw mushrooms cook down to about 1.5 cups. It looks like a mountain going into the pan, but mushrooms are mostly water. I usually make a double batch so there’s enough for leftovers, because they reheat well in a hot skillet the next day.
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Ingredients
500 g (about 4 cups) whole mushrooms -
1 small onion, sliced
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5 cloves garlic, minced
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1/4 cup butter
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2 tablespoons lemon juice
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1 teaspoon olive oil
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1 teaspoon fresh rosemary leaves
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salt and pepper to taste
Step by Step Instructions
Step by Step Instructions
Heat it up
Heat a large cast iron over medium heat and melt butter with oil. Cook onion until tender then add mushrooms.
Cook & add lemon juice
Cook the mushrooms for about 5 minutes until golden brown. Pour in the lemon juice and cook for another 4 minutes.
Nutrition disclaimer
The nutrition information provided is an estimate and is for informational purposes only. I am a Doctor of Pharmacy (Pharm.D.); however, this content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified health provider before making any lifestyle changes or beginning a new nutrition program.
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Get My Macros + Recipes →Frequently Asked Questions
Why are my sauteed mushrooms soggy instead of golden?
I had this problem for years before I figured it out. Two things cause it: crowding the pan and stirring too much. Mushrooms release a lot of water, and if they're piled on top of each other, they steam instead of sear. I cook mine in a single layer with space between each piece, and I don't touch them for the first 2-3 minutes. You need that direct contact with the hot pan for browning. If you have more than 4 cups, I'd do two batches.
What's the best mushroom variety for sauteing?
I've tested cremini, white button, shiitake, and baby bella in this recipe. Cremini are my go-to because they have a meatier texture and deeper flavor than white button. Shiitake are great if you want something more earthy, but I remove the stems because they're too tough. Baby bellas are just mature cremini, so they work the same way. For a keto side dish, any of these keep the carbs low. I'd skip portobello caps here though. They're better stuffed or grilled whole.
Can you freeze sauteed mushrooms?
I've frozen these and they're fine for tossing into stir-fries or soups later, but the texture softens. They won't have that crispy seared edge after thawing. I spread them flat on a sheet pan to freeze individually, then transfer to a bag. They keep about 3 months. When I reheat, I use a hot skillet (not the microwave) to crisp them back up as much as possible.
What can I substitute for butter to make this dairy-free?
I've made these with ghee and with avocado oil. Ghee gives you that buttery richness without the milk solids, so it's my first choice for dairy-free. Avocado oil works too but the flavor is more neutral. I'd skip coconut oil here because it adds a sweetness that clashes with the garlic and rosemary. Whatever you use, the technique stays the same.
Can I add wine or broth to deglaze the pan?
I do this sometimes when I want a little sauce at the bottom. A splash of dry white wine right after the mushrooms brown creates these incredible fond bits. Let it cook off for about 30 seconds before adding the garlic. Bone broth works too if you skip the wine. I've used both, and the wine version has a sharper, more complex flavor. Just keep it to 2 tablespoons or the mushrooms will start steaming.
What protein does this pair best with?
Steak is the obvious answer, and it's my favorite pairing. But I also pile these on grilled chicken thighs, pork chops, and salmon. They're one of those sides that genuinely go with anything. I serve them alongside lemon garlic kale salad and a protein for a full dinner, or next to broccoli cauliflower salad for a lighter plate.
Can I make this recipe ahead of time?
I make a double batch on Sunday and use them throughout the week. They keep in the fridge for 3-4 days in a sealed container. When I reheat, I always use a hot skillet with a tiny bit of butter, never the microwave. The microwave makes them rubbery. A minute or two in a hot pan and they crisp right back up.
These buttery, garlicky mushrooms are my go-to keto side dish when I need something fast that still feels special. They’re vegetarian, so they work for mixed-diet holiday tables, and swapping butter for olive oil makes them vegan. I use rosemary here, but thyme works just as well if that’s what you have on hand.
These pair beautifully with 
