- Steam spinach until wilted, for about 2 minutes.
- Remove from heat, and set aside to cool.
- Combine mushrooms, scallions, onion powder, parsley and breadcrumbs in a mixing bowl.
- Stir in eggs and mozzarella.
- Squeeze excess water from spinach, and chop finely.
- Stir into mushroom mixture, and season with salt and pepper.
- Heat 2 tablespoons oil in a large skillet over medium heat.
- Using a ¼-cup measure, scoop up mushroom mixture, and put into skillet, flattening slightly to form a patty.
- Repeat until skillet is full, but do not overcrowd.
- Pan-fry patties on first side until golden, for about 5 minutes, and turn over.
- Add remaining oil, and pan-fry second side until golden.
- Remove from skillet, and drain on paper towels.
- Repeat until mushroom mixture is used up, adding more oil if needed.
- Serve patties hot or at room temperature.