This sandwich can be made in 10 minutes, 20 if you want caramelized onions.

Recipe after the jump 🙂

Ingredients (serves 2):

• 2 hamburger buns
• 2-4 slices butter lettuce or 1/4 cup arugula
• 2 slices blue cheese
• 2 large portobello mushrooms
• 1 medium yellow onion
• 2 tablespoons balsamic vinegar
• 2 tablespoons olive oil
• 1/3 cup water or stock (chicken or veggie)
• 2 tablespoons butter
• 2 tablespoons mayo
• 2 cloves of garlic, minced
• 1 dash of paprika
• 1 pinch salt, 1 pinch pepper

Caramelized Onion:

I find that onions caramelized faster when cooked in a smaller rather than larger pot, although the process will still require some patience.  Slice raw onion to desired thickness.  In a small pot, melt the butter on low heat.  Add onions and stir occasionally with a spoon, cooking for about 20 minutes on low heat or until the onions have turned translucent and brown.

Toast the buns at 400 degrees F for 5 minutes.

Preparing the Portobello mushroom “patty”:

Clean the mushroom with a paper towel dampened with water.  Taking a spoon, scrap the gills off like below.  The gills tend to give the mushroom a woody flavor and we want to avoid that here.  With a pair of kitchen shears, cut the outer edges of the mushroom off to make the patty as flat and even as possible for cooking.

Heat a medium saute pan on medium to high heat.  Add olive oil.  Put the mushroom in the pan, top side down.  Add olive oil and balsamic vinegar on top.  Sprinkle on salt and pepper or any other dry seasons you’d like.  Add a splash of water or stock to steam the pan.  Cover with a lid and cook for about 3 minutes, flipping the mushrooms over and re-seasoning with balsamic vinegar, salt, and pepper for another 2-3 minutes.  Flip the mushrooms again so that the top side is down.  Put a slice of blue cheese on each patty, cover, and let melt for 1-2 minutes.  Remove patties from the pan.

Garlic Chili Mayo:

In a small bowl, mix the mayo with raw minced garlic and paprika or cayenne powder to taste.

Now it’s time to assemble the sandwich.  Spread the mayo sauce on the toasted buns. Pile on the mushroom patty with cheese, caramelized onion, and butter lettuce or arugula.  That’s it!