Preheat oven to 375 degrees. Spray a large baking dish with cooking spray and set aside.
Wash cauliflower and cut into bite sized pieces. Place cauliflower into a large pot, add 2 cups of water, cover, and bring to boil over high heat. Reduce heat to medium and cook for 8- 10 minutes, or until cauliflower is just starting to get tender. Drain cauliflower in a colander, and place in a large bowl. (Or you could microwave the cauliflower in a large microwave safe dish in 1 cup of water, covered with saran wrap poked with a few holes for steaming. Microwave for 8-12 min or until cauliflower is just starting to get tender. Drain in a colander, and place in a large bowl).
Meanwhile, mix ingredients for sauce together in a small bowl.
Add sauce to cauliflower, and stir until well combined. Pour into baking dish. Sprinkle topping over cauliflower.
Bake 30-35 minutes, or until cheese is melted and topping is lightly golden brown. Serve warm.