Portabella Steak Topping - 16

Recently while my wife was out of town on a shopping trip with the gals, I contacted my high school classmate, friend, and fellow Vietnam vet, Adrian R., and invited him over for an evening of grillin’ and chillin’.  As luck would have it his wife was gone for the evening as well.  I picked up a couple of filets and Yukon gold potatoes and he arrived with salad and the ingredients for this wonderful steak topper or side dish if you prefer.  We cracked a good bottle of red, grilled, dined, and watched Blues hockey and he showed me this simple recipe.  I enjoyed it so much that I recreated it the next three evenings. And while this is prepared entirely inside on the stove, it is to be placed on grilled steaks and since we’re about all things grilling, including toppings for grilled food, we figured it was appropriate for the site.


2 portobella caps (the stems can also be used)
1 white onion
2 tbsp teriyaki marinade (found at most grocers)
2 tbsp unsalted butter (2 more are optional)
salt and pepper to taste

Makes enough for two steaks plus a little more.

Portabella Steak Topping - 1

This particular evening I traveled to the home of the Original Grillin Fool, Scott, to grill a couple of prime sirloins and share this simple, delightful treat with him:

Portabella Steak Topping - 2

Here I’m rough-chopping the white onion while enjoying a good glass of red:

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***Editor’s Note ~ Dad made me promise not to put the picture of him when the onions fumes hit him.  I caught him mid onion headache and is quite comical, but alas, I’ll defer to him and keep it off the site. That being said, for a small fee, I’ll email it to you***

The onion is ready for the skillet:

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Two tablespoons of butter are added to the skillet… OK, looks like I added four.  I’ve always heard two things make food taste better, salt and butter—at least there’s no bacon in this recipe!

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Onion is added and peppered:

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While the onion is sautéing I give the portobella mushrooms a chop after I brushed them clean. Never clean mushrooms under running water.  They suck up the water instead of the flavor from the pan.

Make the chunks fairly good sized as they will shrink a bit when they hit the skillet:

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When the onion becomes golden it’s time to add the mushrooms:

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In they go so they become happy as Emeril says:

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The onion and mushrooms are married and having fun now:

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Meanwhile the steaks are on the Char-Broil Big Easy infrared grill – this grill is simply amazing:

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***Editor’s Note ~ That little filet was for my two sons to split. They both have an affinity for steak. Makes a father proud***

Now the mushrooms and onion are cooking down and right near the end of cooking time I’ll add the Teriyaki marinade:

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Add just a few splashes and stir continuously until the mushrooms and onion are coated and it begins to thicken up. The recipe calls for 2 tbsp, but that’s just a rough guide. If you go higher or lower by a little, you’ll be fine:

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The mixture has thickened nicely and is ready to serve:

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And here it is plated over one of those prime sirloins:

Portabella Steak Topping - 16

The mixture tops a perfectly grilled medium-rare steak and was a very tasty addition to the menu.  I’ve also served this as a side dish—a perfect complement to many entrees.  Other mushrooms could be added and a variety of wild mushrooms would be spectacular.  In addition, many other marinades or sauces could be substituted to please a variety of tastes.  Give this a try soon and it will become a favorite.

If you have any questions or comments about this post, feel free to leave them below or shoot me an email.

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Portobella, Onion, and Teryaki Steak Topper
Recipe type: Steak Topper
Cuisine: BBQ
Prep time: 
Cook time: 
Total time: 
Serves: 4
Portobello and onion topper, perfect for any steak
  • 2 portobella caps (the stems can also be used)
  • 1 white onion
  • 2 tbsp teriyaki marinade (found at most grocers)
  • 2 tbsp unsalted butter (2 more are optional)
  • salt and pepper to taste
  1. Put the butter in a skillet to melt
  2. Rough chop the onion and add to the butter
  3. While the onion sautés, chop the mushroom into large chunks
  4. When the onion becomes golden brown, add the mushrooms
  5. After a few minutes, the mushrooms and onions cook down, add the teriyaki marinade, stirring continuously
  6. Keep simmering until the liquid thickens
  7. Then spoon over each steak

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