Clean mushrooms and trim stems. Brush the tops with olive oil and lay them upside down on a baking pan. Chop the stems and set them aside.
2
Wash the spinach thoroughly, until no more sand appears in the washing water. Remove any tough stems. Cook until barely tender just in the water clinging to the leaves. Press out excess water and chop coarsely. Mix with the chorizo, egg and stems.
3
Fill mushroom caps with the mixture. Bake at 350 F/180 C until the mushrooms are tender and the filling cooked, about 20 minutes, depending on the size of the mushrooms. Serve hot.
