• Preheat oven to 400℉ or 204℃

Prepare the Mushrooms

• Begin with removing the mushroom stems (save for the filling) by using a knife or popping off with your fingers. Use a spoon to scoop out most of the brown gills.
• Place in an oven-safe dish or baking sheet.

Make the Blue Cheese Filing

• Chop the onion and mushroom stems.
• In medium-sized saucepan, melt the butter over medium heat. 
• Add the onion and mushroom stems to the pan. Sauté for 2-3 minutes, until the onions turn translucent. 
• Add the garlic and sauté until aromatic, about 20 seconds. Add the blue cheese and stir continuously as the cheese begins to melt and oils release - about 1 minute. 
• Add the panko breadcrumbs to the pan along with the parsley. Stir to combine and remove from the heat. 

Stuff the Mushrooms and Bake

• Using a spoon, fill the mushroom caps with the blue cheese stuffing. 
• Place in the preheated oven and bake 10 minutes. Remove from the dish from the oven and sprinkle shredded cheddar cheese on top of each mushroom distributing evenly. Place back in the oven and bake for another 10 minutes. 
• Remove from the oven and serve.
• Enjoy!