Step 1

Make your marinade in a large Tupperware or shallow bowl, by adding olive oil, steak spice seasoning, bbq sauce or vegan Worcestershire, balsamic vinegar, and liquid smoke. Whisk everything in the bowl until combined.

Step 2

Place the mushroom caps into the bowl and brush the marinade all over the mushrooms (top & bottom). They do not need to be submerged in the marinade or anything- but they should be coated completely. Allow the mushrooms to sit stem-side up & allow them to marinate for 20-30 mins minimum in the fridge. The longer you marinate the stronger the flavour will be. You could marinate overnight.

Step 3

When ready to cook, heat a pan over medium-high heat, and pour in a little bit of the leftover marinade, and discard the rest but keep the bowl.

Step 4

When piping hot, add the mushrooms to the pan, stem-side down, leaving plenty of space between them. Allow them to cook for 3-5 mins until the liquid begins to release.

Step 5

Reduce heat to medium.

Step 6

Take a heavy cast iron pan (or something slightly heavy), and place it on top of the mushrooms to flatten the portobello mushrooms. Press to flatten gently. Cook for another 2 mins.

Step 7

Flip the mushrooms, and repeat flattening with a cast iron pan for a few minutes. You can add some water to deglaze the pan if you wish.

Step 8

Remove the cast iron pan, and flip again so they are stem-side down. Turn the heat back up again.

Step 9

Allow the mushrooms to cook until the liquid is evaporated, roughly 3-5 mins.

Step 10

Next, remove from the heat

Step 11

If you want to BBQ your portobello mushrooms for a smokey grilled and char taste, first place the mushrooms into a bowl and toss with a few tbsp of my Guinness BBQ sauce or BBQ sauce of choice.

Step 12

Preheat your BBQ to medium-high heat.

Step 13

Sear the portobello mushrooms on the grill for a couple of minutes on each side, until you get a slight char. Transfer to a cutting board, and thinly slice.

Step 14

Meanwhile, smear a bit of butter on the face of each bun, and toast on the grill until nicely charred.

Step 15

Spread some BBQ sauce on the bottom of each bun and place a handful of greens, topped with a generous pile of mushrooms slices.

Step 16

I added some caramelized onions and a drizzle of my Guinness beer cheese.

Step 17

To make caramelized onions for your sandwich, heat 1 tbsp olive oil in your pan, over medium-high heat.

Step 18

Add red onions and a pinch of salt and cook 8-10 mins, until caramelized, adding a little bit of water as needed to deglaze the pan.

Step 19

To make a creamy beer cheese sauce for your sandwich, start by melting ¼ cup butter in a medium saucepan over medium heat.

Step 20

Whisk in the ¼ cup flour, and cook for 2 mins, whisking constantly.

Step 21

Add the 1 tbsp mustard, and slowly begin pouring in ⅓ cup Guinness or beer of choice, whisking constantly. Cook for 1-2 mins, whisking. FYI if you're worried about adding alcohol just know that the alcohol gets cooked out of the beer.

Step 22

Then slowly whisk in 1 cup of soy milk or oat milk. Whisk until you smooth.

Step 23

Turn down to medium-low and add your dairy-free shredded cheese, stirring to help it melt. You can add more of your milk until you reach your desired consistency. I like a pourable sauce. Voila!