Preheat the oven to 425°F. Line 2 rimmed baking sheets with zero-calorie nonstick cooking spray.
Combine the cauliflower, celery, mushrooms, leeks, onion, and garlic in a large bowl. Sprinkle with salt, pepper, and seasoning, to taste. Stir well to combine.
Spread in an even layer on the baking sheets.
Roast in the oven for 40-45 minutes, until golden brown. Remove from the oven. Serve warmly.
Notes
For Flex™ Patients: Top with crushed walnuts (4). Recipe Yields: 34 servings of vegetables.