Preheat oven to 450°F.
Clean mushrooms gently with a damp paper towel (don’t submerge in water). Pop off the stems and remove gills with a small spoon. Brush tops with olive oil. Bake mushrooms cap sides up for 5-10 min on a greased wire rack or until brown.
Remove from the oven and let them remain cap side up for another 15 minutes to make sure all the moisture has drained. Lower oven temp to 375°F.
In a large skillet pour a tablespoon of olive oil over medium high heat and sauté the minced garlic and shallots for 2-3 minutes.
Add the sausage, breaking it apart with a wooden spoon into small pieces until fully cooked.
Reduce heat to low and add marjoram, thyme, sage, salt, pepper, and panko crumbs; cook for 2 minutes stirring constantly.
Add the cream cheese and keep stirring until it’s fully melted.
Remove skillet from the heat and stir in cheddar and Parmesan cheeses.
Turn mushroom caps over. Spoon sausage mixture into mushroom caps, stuffing them as full as possible.
Bake for 10-15 minutes or until slightly browned on top. Remove from oven, sprinkle with minced parsley and serve.