Preheat your oven on medium heat to 350°F (175°C).
In a large mixing bowl, combine the heavy cream, cream cheese, about two-thirds of the shredded cheese, garlic powder, seasoning, and sour cream. Mix until smooth.
Fold in the cauliflower florets, broccoli florets, and diced ham.
Transfer the mixture to a lightly greased casserole dish.
Sprinkle the remaining 1/2 cup of cheese on top.
Bake for 30-35 minutes or until the cheese is bubbly and golden.
Garnish with chopped green onions before serving.