Preheat oven to 450 degrees F. Heavily grease baking sheet with butter. Divide cauliflower into bite sized chunks.In a large bowl, combine flour, water, olive oil, garlic powder and salt until well combined. Add cauliflower and gently toss to coat each piece evenly. Transfer coated cauliflower to prepared baking and bake in preheated oven for 15 minutes, turning once halfway through cooking time. Remove from oven.In large bowl, combine hot sauce and melted butter. Add partially cooked cauliflower and gently toss to evenly coat. Return cauliflower to baking sheet and continue cooking for an additional 20-25 minutes, turning once, until pieces start to turn golden brown.Remove from oven and serve warm with blue cheese dressing and fresh celery sticks.