Heat olive oil in large skillet. Add chorizo and cook on medium heat for 3-4 minute Add chopped mushroom stems and sweet potato. Cook for 5-6 more minutes, until mushrooms release their moisture and begin to dry.
Add onion and garlic, cook until fragrant and slightly transparent, another 2-3 minute Season with paprika, salt, and pepper and cook for 1-2 minutes more.
Remove from stove and allow to cool. Stir in chopped parsley and grated parmesan.
Preheat oven to 400 deg.
With mushroom caps arranged in a baking dish, add 1-2 tbsp stuffing to each. Sprinkle tops with panko and bake for 20-30 minute.