INGREDIENTS:
1 large head of broccoli (about 8 cups, and cut into large florets)
1 1/2 cups mayonnaise
1 1/2 cups sour cream
1/4 cup melted butter
1 -2 teaspoon garlic powder (or to taste)
2 teaspoons seasoning salt
1 teaspoon black pepper
1 1/2 cups old cheddar cheese (cut into about 1/2-inch cubes or shredded)
1 small onion, finely chopped
1/2 cup parmesan cheese (or to taste)

Directions:
1 Set oven to 350 degrees.
2 Butter a 2-quart casserole dish (or use any size desired to hold the broccoli mixture).
3 Steam or boil the broccoli florets until JUST fork tender (do not over cook) drain well then pat dry with paper towels.
4 In a medium bowl combine the mayonnaise with sour cream, melted butter, garlic powder, seasoned salt, black pepper, cheddar cheese cubes and onion; mix well to combine.
5 Add in the well drained broccoli florets and mix gently with a spatula.
6 Transfer to prepared baking dish.
7 Sprinkle with grated parmesan cheese.
8 Bake uncovered for about 20-25 minutes or until bubbly (the cheddar cubes do not have to be completely melted!).

Source : allrecipes.com