1. Prepare the cauliflower base: Start by washing and cutting the cauliflower into florets. Steam the cauliflower until it is very tender, about 8-10 minutes. You should be able to easily pierce it with a fork. Drain any excess water thoroughly, as too much moisture can make the dip watery.

2. Mash the cauliflower: Transfer the steamed cauliflower to a large mixing bowl. Add the softened cream cheese, Greek yogurt, buffalo sauce, garlic powder, and onion powder. Use a potato masher or a fork to mash everything together until mostly smooth. A few small lumps are fine and add texture. Season with salt and pepper to taste.

3. Combine with chicken: Stir in the shredded or diced cooked chicken into the cauliflower mixture. Make sure the chicken is evenly coated with the buffalo-cauliflower base.

4. Assemble the casserole: Transfer the mixture to a 9×13 inch baking dish or an oven-safe skillet. Spread it evenly across the bottom of the dish.

5. Add the cheese topping: Sprinkle the shredded cheddar cheese evenly over the top of the dip. If using, scatter the crumbled blue cheese over the cheddar.

6. Bake to perfection: Bake in a preheated oven at 375 F (190 C) for 20-25 minutes, or until the cheese is melted, bubbly, and slightly golden brown. The dip should be heated through.

7. Garnish and serve: Once out of the oven, let it cool for a few minutes. Drizzle with a little extra buffalo sauce if desired, and garnish with fresh chopped chives or green onions before serving.