1. Heat oil in pot on medium-high. Add onions; cook 7 minutes. Add curry and ginger; cook 1 minute.
2. Add next 5 ingredients (through cilantro). Partly cover; simmer on medium-low for 30 minutes.
3. Whisk cornstarch and water; stir into pot. Cook on high 1 minute. Add salt and pepper to taste. Garnish with cilantro.