Button mushrooms are young white or light brown mushrooms that are round and thick. When they mature, their caps open and darken to a deep brown, becoming Portobello mushrooms. This recipe uses whole portobello mushrooms stuffed with ground pork and baked. Remove the mushroom stems, mix the ground pork with water and seasonings, then stuff the mushrooms. After steaming and baking, the mushrooms become fragrant and juicy, blending the flavors of the meat and mushrooms. Baked stuffed mushrooms are easy to make, perfect for family meals, gatherings, or parties.