Steam cauliflower until crisp-tender, about 4 minutes. Transfer to bowl; sprinkle with salt and pepper.
Sprinkle lamb with salt, pepper, and 3/4 teaspoon curry powder. Heat oil in medium skillet over medium-high heat. Sauté lamb to desired doneness, 4 to 5 minutes per side for medium-rare. Transfer to plates. Pour off oil from skillet.
Add 1 1/4 teaspoons curry powder and flour to skillet; whisk 15 seconds. Add broth, cream, and chutney. Boil until thick, whisking, 2 minutes. Add cauliflower and half of green onions; toss to heat through.
Spoon curried cauliflower over lamb. Sprinkle with remaining green onions.
