- Place steak in a large resealable plastic bag; add vinaigrette. Seal bag, turning to coat. Refrigerate 12 hours, turning occasionally.
- Preheat oven to 425°F. In a large bowl combine cauliflower, onion and oil; toss to coat. Spread vegetables in a single layer on a rimmed baking sheet. Bake 20 minutes, stirring once. Remove pan from oven. Drizzle vinegar on vegetables; toss to coat. Sprinkle with cheese. Return to oven; bake 8–10 minutes more.
- Meanwhile, coat a large nonstick skillet or grill pan with nonstick cooking spray. Place over medium heat until hot. Remove steak from marinade; discard marinade. Sprinkle steak with thyme, and season with pepper to taste.
- Place steak in skillet; cook, partially covered, 4–5 minutes per side (145°F for medium-rare) or to desired doneness. Transfer steak to a platter. Let stand 5 minutes.
- Thinly slice steak against the grain, and serve with roasted vegetables.
per serving: 225 calories, 8g fat, 3g saturated fat, 75mg cholesterol, 190mg sodium, 7g carbohydrate, 2g fiber, 3g sugars, 31g protein