If you can’t find mizuna, spinach would be a fine substitute. Take care to drizzle the soy sauce onto the greens and then top with the eggs — this will prevent the eggs from turning an unappetizing brown color.
1. In Dutch oven heat 1 tablespoon oil over medium-high heat. Add ginger. Cook about 2 minutes or until it softens slightly. Add mizuna and 1/4 cup water. Reduce heat to medium. Cook, stirring occasionally, about 10 minutes or until tender.
2. Meanwhile, in small bowl beat together eggs, mirin, sugar and salt. In small skillet heat 1 teaspoon oil over medium heat. Add egg mixture. Cook until eggs set on bottom. Use spatula to lift cook portions of eggs, allowing uncooked portions to flow underneath. Continue cooking and lifting eggs until set. Remove from heat.
3. Drain greens, pressing with back of spoon to remove excess liquid. Transfer to serving dish. Sprinkle with soy sauce. Top with eggs. Serve hot.