Prepare pasta according to package instructions.

In a steamer, add the broccoli. Place on a stove over medium heat and cover with a lid. Let it cook for about 8-10 minutes.
Test the broccoli for softness with a fork. Broccoli should not be so soft it's falling apart.

Note: If you don't have a steamer, you can do this step in a pot of water. Bring water to a boil. Place the broccoli in the boiling water for 5-8 minutes or until tender. Remove from water into a bowl and set aside.

Add unsalted butter to large pot over medium heat. Let the butter melt - do not let burn. If necessary, reduce the heat to low.

Add onion and garlic. Sauté for 5-7 minutes, or until the onion is soft. Stir occasionally.

Add the cream cheese, blue cheese and spices. Stir occasionally until the cream cheese is melted. Then add the heavy cream. Let the cream warm. Add mozzarella and cheddar. Stir constantly until you get a creamy texture and the cheeses begin to melt.

Remove from the heat and add creamy sauce to the pasta. Stir well until combined. Add the broccoli and mix.

Preheat the oven to 375F.

Transfer broccoli mac and cheese to an oven safe casserole dish. Sprinkle with additional mozzarella and cheddar then bake in for 10 minutes or until lightly golden brown.

Remove from the oven and serve warm.