
8 or 9 years ago on business I was traveling in St. Louis. It was late. The restaurant I wanted to go for dinner was closed that evening and I had an early day the next morning. So, I went to a local grill on a flyer. I don’t even remember the name and never went back. Nothing on the menu appeared appetizing so I settled on the portobello burger. It was the best part of the trip!
I hadn’t thought about that sandwich in years. It came to mind about a week ago as we were discussing various dishes, things to eat during the week and some beautiful portobello mushrooms at the market. We also had some frozen red sauce from a prior meal that would be just enough for the sandwich. This is my take on that bar and grill’s sandwich. The mushrooms give the sandwich body and meatiness. The Italian red sauce adds depth of flavor and character. The pesto gives the sandwich a floral quality and creaminess to go along with the provolone and parmesan cheese. This is one beautiful sandwich, even i I say so myself.
Ingredients
- 6 portobello mushrooms
- 1 pt Italian Red Sauce (for a recipe click here)
- 1/2 cup pesto
- 3 slices provolone cheese
- 1/2 cup parmesan cheese. grated
- 1/2 large yellow onion, sliced and caramelized
- olive oil
- lettuce leaves
- tomato slices
- 3 Kaiser rolls
Instructions
Caramelize the onions. Slice the onion in 1/4 inch rings and separate. Heat a sauté pan. When hot, add 2 Tbsp olive oil to a sauté pan. Add the onion rings and sauté over medium heat tossing periodically until the onions have turned a beautiful golden brown. Remove from heat and set aside.
Cook the Mushrooms. First, remove the stems and gills (spores) from the mushrooms. I find the gills provide an unwelcome spongy texture and discolor anything with which they come in contact.

Next oil the mushrooms.

Season with salt and fresh ground pepper to taste. Preheat a gas grill on medium heat. Place the mushrooms on the grill and cook the mushrooms on both sides.

When the mushrooms have cooked, lay the mushrooms top side down on the grill. Put a slice of provolone cheese on three of the mushroom caps. Put a cap on top of each provolone cheese slice (like a double meat hamburger) and then put parmesan cheese on the top cap.

Turn off the grill, place the Kaiser rolls on the grill and cover to toast the Kaiser rolls and melt the cheese.

Assemble the sandwich. Generously slather the bottom piece of the Kaiser roll with the Italian red sauce. Slather the top of the Kaiser roll with the pesto. Place the mushroom caps on top of the red sauce. Add the caramelized onions on top of the mushroom caps, followed by the tomato and then the lettuce.

Serve and enjoy, as I’m sure you will. 🙂
I have been walking past really great looking mushrooms at the grocery store for weeks and now I know what to do with them. This looks fantastic. I better get some propane for my gas grill.
I adore meaty portobello shrooms on the grill.
oh my gosh! This looks so amazing! It has all my favourite ingredients!! Can’t get any better than this!! 🙂