Hearty & Slow Cooked Portobello Mushrooms Recipe

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Perfect for both winter and summer, these portobello steaks are so simple to throw together and the results are so delicious that they are as welcome for a simple family meal as they are as the centrepiece at a dinner party.

Seriously umami-rich and meaty, my recipe packs these mushrooms full of complex flavours that can impress even those who are ardent carnivores or the mushroom-haters out there!

Topped with some chimichurri sauce – a traditional topping for grilled meats – and served alongside something like my roasted parsnip puree or sweet potato mash and you have the recipe for an incredibly flavourful and hearty plant-based meal!

Slow Cooked Portobello Served with Chimichurri
Slow Cooked Portobellos Served with Chimichurri

How to Make Braised Portobello Steaks

I’m not going to sit and pretend that these portobello have the same texture and flavour as steak (or any other meat), however, they share similar characteristics that they can be a fantastic stand-in if you’re looking for a unique main dish that isn’t necessarily meat-based.

And the benefit of this recipe is that it quite literally requires about five minutes of active time – as opposed to my portobello mushroom stew which is a bit more involved. Because it’s cooked in such a low oven, you don’t even need to wait long for it to preheat! But that is the first step – preheat your oven to 150°C (300°F).

Ingredients for this recipe
Ingredients for this recipe

Meanwhile, go ahead and remove the stems from your portobello mushrooms, but keep them whole. And that’s all the prep you need to do to the mushrooms!

Now, turn your attention to the cooking liquid. In a large dutch oven, whisk together some olive oil, soy sauce (this adds a nice complexity of flavour), sherry vinegar (you can use balsamic or red wine vinegar, too), tomato paste, some whole coriander seeds, a pinch of red chili flakes, a good amount of salt and a few grinds of black pepper.

Preparing the braising liquid
Preparing the braising liquid

Then, crush several cloves of garlic with the flat side of your knife and then remove the peels. Leave them whole and toss them into the pot. They will get so sweet, tender and flavourful as the cook.

Finally, remove the peels from a shallot and cut it into quarters through the root end. Toss these into the pot, as well, along with a few sprigs of fresh oregano.

Adding the shallots, garlic and herbs
Adding the shallots, garlic and herbs

You can use fresh thyme here, as well, or even marjoram. A combination of any of these would also be good.

Next, arrange the portobellos with the gills facing downwards over the aromatics. Don’t worry if they are not really submerged in the liquid – they will shrink significantly as they cook and end up in the liquid eventually!

Adding the mushrooms to the pot
Adding the mushrooms to the pot

Place a piece of parchment paper over the mushrooms – this is to prevent the liquid from evaporating too much and will allow the mushrooms to reabsorb the flavour.

Then, place the lid over the pot and move it to the oven.

Covering the mushrooms with parchment paper
Covering the mushrooms with parchment paper

Braise the mushrooms for about an hour (or longer) before removing the pot from the oven and flipping them over. Replace the parchment and then cook for a further fifteen to twenty minutes.

You can even cook them longer as it’s essentially impossible to overcook mushrooms and they won’t burn at this low temperature.

Removing the pot from the oven
Removing the pot from the oven

Once the mushrooms are done, remove them from the pot and arrange them – along with the shallot and garlic – on a serving platter.

Drizzle with a bit of the cooking oil and top with some homemade chimichurri. This adds such a nice bright punch of acidity that pairs so well with these deeply savoury mushrooms.

Slow Cooked Portobello Mushrooms

Slow Cooked Portobello Mushrooms

Deliciously meaty and umami-rich, these portobello "steaks" are simple to throw together for an impressive main dish for any occasion and any season. Don't let the long cooking time intimidate you, there is very little prep and active time required.
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Servings 2
Prep Time 5 minutes
Total Time 1 hour 25 minutes


  • 60 ml (¼ cup) olive oil
  • 1 tbsp soy sauce
  • 1 tbsp sherry vinegar
  • 1 tbsp tomato paste
  • 1 tsp whole coriander seeds
  • ½ tsp chili flakes
  • 6 cloves garlic lightly crushed and peels removed
  • 1 large shallot peeled and cut into quarters through the root end
  • 2-3 sprigs fresh oregano (optional)
  • 4 large portobello mushrooms stems removed but left whole
  • Chimichurri for serving (optional)


  • Preheat oven to 150°C (300°F). In a large Dutch oven (or oven-safe pot with a lid), add the olive oil, soy sauce, sherry vinegar, tomato paste, coriander seeds and chili flakes along with a generous pinch of salt and a few grinds of black pepper. Whisk to combine.
    Preparing the braising liquid
  • Add the garlic, shallot and oregano. Arrange the mushrooms, gills facing down, over the aromatics.
    Adding the mushrooms to the pot
  • Press a piece of parchment paper so that it covers the mushrooms. Place the lid on the pot and move to the oven.
    Covering the mushrooms with parchment paper
  • Roast the mushrooms for 1 hour before removing from the oven. Remove the parchment and flip the mushrooms over so that the gills are facing up. Replace the parchment and the lid and cook for a further 15 minutes in the oven.
    Removing the pot from the oven
  • Transfer the mushrooms to a serving platter, cutting them in half, if desired. Scatter the shallots and the garlic over the mushrooms and drizzle with some of the cooking liquid. Top with chimichurri, if using.
    Serving the mushrooms


Calories: 82kcal | Carbohydrates: 16g | Protein: 6g | Fat: 1g | Saturated Fat: 0.2g | Polyunsaturated Fat: 0.3g | Monounsaturated Fat: 0.2g | Trans Fat: 0.01g | Sodium: 594mg | Potassium: 840mg | Fiber: 5g | Sugar: 7g | Vitamin A: 306IU | Vitamin C: 6mg | Calcium: 72mg | Iron: 2mg

Disclaimer: Nutritional information is automatically generated and provided as guidance only. Accuracy is not guaranteed.

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And that is all there is to one of the most delicious and flavourful plant-based meals you can make. After only about 5 minutes of work, you can just kick back and relax as these mushrooms slowly cook in a low oven.

Are you looking for a great recipe for portobello steaks? Have any questions? Let me know in the comments!

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Maggie is the creator behind No Frills Kitchen. She is a world traveller, home cook and recipe developer who loves to experiment with new cuisines and techniques at every chance she gets. No stranger to improvising and making do with the equipment and ingredients she has available, she is passionate about sharing her knowledge with others. Read More

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