Heat the oil in a Dutch oven over medium-high heat. Add onion and ginger; cover and cook 3 minutes, stirring frequently. Reduce heat to medium. Add Mild Curry Powder and garlic; cook 30 seconds, stirring constantly. Add cauliflower and next 4 ingredients (cauliflower through salt), stirring well to combine. Bring to a boil (yogurt will curdle); cover, reduce heat, and simmer 20 minutes or until cauliflower is tender. Serve with lemon wedges and cilantro sprigs, if desired.