This are OH SO YUMMY! I would take one of these over a steak any day of the week. My 20 year old son begs me to make them when he comes to visit on the weekends. They are so meaty and filling it's unbelievable. I make an avocado salsa to put on them that is just incredible as well. Make sure you check out that recipe as well.
Break or cut cap off mushroom. Clean with a damp paper towel or clean tea towel. Do not submerge mushroom in water to clean.
Brush with olive oil or Zesty Italian dressing between the gills and then turn the mushroom over and lay in either olive oil or Zesty Italian dressing to marinate for at least one hour. Preheat grill to Medium-Medium high.
Right before grilling, shake excess marinate off.Season the side you are placing down first with salt and pepper. (I use garlic salt and pepper) Place on hot grill. Season side facing up right away with salt and pepper. (or garlic salt and pepper) Grill on each side until mushroom starts to shrivel or lose it's shape slightly. You want it to either start to caramelize or get deep/dark grill marks. Be patient, this can take time.
Right before you pull the mushrooms off the grill, place a slice (I use 2) of Havarti cheese on top of each mushroom and close the lid for 30 seconds. It will melt fast.
Serve topped with Avocado salsa (see my recipe) or baby arugula or spinach and either some homemade strawberry vinaigrette or mustard vinaigrette. Enjoy!