Grilled Flank Steak Stuffed with Mushrooms and Blue Cheese

Flank Steak (with Horseradish Sauce)

Flank Steak (with Horseradish Sauce)

by Cat, June 2012 (photo, right, from (3))

Flank steak is a natural for the grill, but of course it can also be pan-grilled or broiled. And the leftovers are great in salads – if there are any leftovers.

London Broil is probably the most well-known way to prepare flank steak, but the cut is very versatile and works well with sauces, marinades, and also being stuffed with good things, as in this recipe.

Some recipes require cutting a pocket in the steak; in my experience, this is best done by the butcher – don’t be afraid to ask.

For many recipes, you can use flank steak, skirt steak or hangar steak  – all come from the belly of the steer. Flank steak is usually more readily available of the three cuts. See (2) for great photos and descriptions of the various belly cuts.

2020 Note: I’m getting lazy in my old age, so I make this recipe without making a pocket in the steak. Instead, I just serve the grilled steak with the mushroom and blue cheese sauce on top. Mmm.

Grilled Flank Steak Stuffed with Mushrooms and Blue Cheese

Back in the early 1970s when I was learning how to cook gourmet recipes, I happened on a great little cookbook: Charcoal Cookbook, by Ed Callahan & published by Nitty Gritty Productions (1). And that’s where I found this great recipe. It also has recipes for lamb, pork, wild game, seafood, poultry, veggies, appetizers, and even dessert fruits.

At the time, the small hibachi was just becoming popular, and was useful for those who lived in flats with a small balcony but no yard. Charcoal briquettes provided the flame. Now many of us have gas grills, but I still prefer the flavor of a charcoal grill, provided the coals are NOT lit with starter fluid.

As I advised above, ask your butcher to make the pocket in your steak. Any blue cheese will work, but my favorite for this recipe is gorgonzola. You can use button or crimini mushrooms from the produce market, reconstitute dried mushrooms, or gather some wild mushrooms.

The original recipe calls for 2 Tbsp each butter and blue cheese, but I like to double this, using half in the pocket and half to brush on the outer steak after turning. You can do the prep and stuff the steak several hours in advance if you wish, letting the steak rest in the fridge until you are ready to prepare the grill. Then let it warm at room temperature while the grill heats up, giving the steak time to shake off the fridge-chill.

The original serves 6; I’ve added a version that serves 2.

Ingredients & Equipment

  • 6 servings:
  • one 3-lb flank or other tender steak, with pocket
  • ½ lb fresh or 1 – 1.5 oz dried mushrooms, reconstituted, sliced
  • 4 – 6 Tbsp real butter, preferably from pastured cows
  • 4 Tbsp crumbled blue cheese
  • 1 clove garlic
  • Unrefined sea salt and freshly ground black pepper
  • 2 servings:
  • one 8-oz flank or other tender steak, with pocket
  • 3 – 4 oz fresh or ¼ – ⅜  oz dried mushrooms, reconstituted, sliced
  • 2 – 3 Tbsp butter
  • 2 Tbsp crumbled blue cheese, preferably from pastured cows
  • 1 small clove garlic
  • Unrefined sea salt and freshly ground black pepper
  • Equipment:
  • charcoal or gas grill (I prefer charcoal)
  • or stovetop cast iron grill pan


  1. If using dried mushrooms, reconstitute them (2 – 30 minutes, depending on temperature of water); they should already be sliced.
  2. Prepare grill, and oil the grate.
  3. If your butcher didn’t do this for you, cut a pocket in the steak (or skip the pocket).
  4. Peel, then mince garlic. Sprinkle with ¼ tsp salt, then crush to a pulp with the side of a knife blade.
  5. Slice mushrooms and sauté in 1 Tbsp of the butter until soft. Add cheese and remaining butter. Season to taste.
  6. Fill pocket with mushrooms and half of butter-cheese sauce. Close the pocket with skewers. NOTE: You can prepare up to this point in advance, keeping the stuffed steak in your fridge until ready to grill. Or you can skip this step.
  7. Broil steak 3″ from coals, until charred, about 3 – 5 minutes. Turn it over, brush with reserved sauce, then season with salt and pepper. Grill on second side until steak is rare or medium-rare. Remove from grill to cutting board.
  8. If you didn’t cut the pocket, serve the steak with the mushrooms and sauce on top.
  9. Slice in thin diagonal slices against the grain and serve.


2/25/18: While I’ve made this many times as written, using my Hibachi, it is now in the middle of winter here in NW Montana, so I decided to try this recipe with a NewYork steak, grilled on my stovetop. The cut is too thin to cut a pocket, so I will use the stuffing ingredients as a sauce over the steak. Used an 8-oz steak, 4 oz cremini mushrooms, 2 Tbsp each butter and gorgonzola, and a small clove of garlic, minced. Added an additional Tbsp butter (3 Tbsp total). I updated recipe accordingly. Result: I served this with Balsamic-drizzed, oven-roasted Brussels sprouts, a small steamed potato, and a portion of cooked beetroot. The steak is almost as wonderful as when cooked on the hibachi – the mushroom/gorgonzola/butter sauce is what makes this a hit. The combination with the Brussels sprouts is excellent.

2/3/21: Tried this with 8 oz flat-iron steak (cut in half for 2 ea 4 oz steaks), and grilled them separately on stovetop in my cast iron skillet. For each 4-oz steak (two separate meals): used 1 garlic clove (minced and pressed with salt), 2 cremini mushrooms (sliced in half and then each half into 1/8 – 1/4 inch slices), 1 Tbsp gorgonzola crumbles and 2 Tbsp butter. Made as before and served with a mix of braised broccoli and Brussels sprouts, and a bi too steamed beet. Delicious!


  1. Charcoal Cookbook, by Ed Callahan & published by Nitty Gritty Productions
  2. (

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