Clean the portobello mushroom caps with a damp cloth, remove the stem and scrape out the gills so you have a well deep enough for the egg.
Rub a little bit of olive oil on the outside of the mushroom to help it cook and keep it from sticking to the pan. Arrange the caps on a baking sheet.
Place one slice of prosciutto inside the mushroom cap.
Crack each egg into a small bowl and then carefully slide it onto a prosciutto-filled mushroom cap.
Sprinkle with black pepper and fresh herbs of choice – parsley can be used and thyme would be great as well. (The prosciutto is salty so adding more is not recommend)
Carefully place the baking pan into the pre-heated 375 degree Fahrenheit oven and bake for 20-30 minutes. The amount of time required depends on how thick your mushrooms are and how done you like your eggs.