Rinse your mushrooms and scoop out the inside with a metal spoon. Dry with a paper towel. Place on a parchment lined oven pan.
Drain and chop the artichoke hearts. In a bowl, mix the artichoke hearts, cream cheese, sun-dried tomatoes, garlic, and shredded Parmesan cheese.
With a pastry brush, brush the mushrooms with olive oil on each side. Sprinkle with kosher salt, pepper, and oregano. Place in oven for 5-7 minutes on each side until brown in a 400 degree oven.
Stuff with artichoke mixture and place a slice of cheese on the top of each mushroom. Place back in the oven and bake until the cheese begins to brown, about 10 minutes, at 400 degrees.