PREHEAT oven to 425°F (220°C). Remove outer leaves from cauliflower and trim stem, leaving head intact, so that cauliflower will sit flat. Place cauliflower in large microwave-safe bowl; add water. Microwave on HIGH 10 minutes. Transfer cauliflower to foil-lined baking pan.
MIX melted butter and Buffalo Wings Sauce in small bowl. Brush cauliflower with mixture, making sure to brush into crevices and between florets.
ROAST 30 to 35 minutes or until nicely browned.
MEANWHILE, place shredded cheeses in large bowl. Add corn starch and toss until cheese is coated. Bring wine to simmer in small saucepan. Gradually add cheese, stirring constantly until melted and smooth. Remove from heat; stir in garlic powder and ground mustard.
TRANSFER cauliflower to serving platter. Pour half of the hot cheese fondue mixture over the cauliflower. Drizzle with additional Buffalo Wings Sauce. Place remaining fondue in small serving bowl. Cut roasted cauliflower into bite-size pieces and serve with remaining fondue cheese for dipping.
Test Kitchen Tip: Want to skip the wine? Substitute an equal amount of chicken broth and add 2 tablespoons (30ml) lemon juice.