In a large pot, bring salted water to a boil. Add the cauliflower florets and cook for about 5-7 minutes or until tender, but still firm. Drain and set aside.
In a mixing bowl, combine the cream cheese, sour cream, garlic powder, onion powder, smoked paprika, salt, and pepper. Mix until smooth and well-blended.
Stir in the shredded cheddar cheese and half of the Parmesan cheese into the cream cheese mixture until evenly incorporated.
Add the drained cauliflower florets into the cheese mixture and gently fold to coat each floret evenly.
Transfer the cauliflower and cheese mixture into a greased baking dish (around 9x13 inches).
Optional: If you want a crispy topping, mix the breadcrumbs with the remaining Parmesan cheese and sprinkle evenly over the casserole.
Bake in the preheated oven for 25-30 minutes, or until the top is golden and bubbly.
Remove from the oven and let cool for a few minutes before serving.
Garnish with chopped chives or parsley for a pop of color.