Green Beans With Miso Butter Braised Onions

Ingredients

• 1 to 1 ½ lb (450g-675g) green beans, washed and trimmed
• 2 lb small onions, or 9-10 small onions weighing about 100g each
• 7 tbsp (98g) unsalted butter, melted
• 7 tbsp (105g) white or yellow miso paste – note 1
• 3 C warm water
• 2 tbsp cornstarch, whisked with 2 tbsp cold water
• Salt for blanching green beans