These heat-tolerant Japanese varieties of spinach are a perfect summer vegetable. In Asia, spinach is commonly used in soups. The Chinese also cook it with noodles and stir-fries. The Japanese braise it and serve it topped with sesame dressing. In India, spinach is pureed with spices and butter. Rich in vitamins A and B2 and minerals such as iron and calcium, these two varieties can be prepared as you would cool-weather varieties of spinach.