Preheat oven to 400 degrees F.

Begin by adding the broccoli and cauliflower to a lightly greased 11x7 baking dish. Place the baking dish in the oven and allow the vegetables to roast for 10 minutes while you prepare the cheese sauce.

Brown the bacon pieces over medium heat until crisp in a medium-sized skillet. When the bacon has browned, remove from the skillet and set aside. Drain off all of the bacon grease except about 1-2 teaspoons.

Reduce the heat to low, add the minced garlic, and saute until fragrant.

Add the milk, heavy cream, and cream cheese. Stir until the cream cheese has melted completely. Stir in one cup of cheddar cheese until melted. Bring the cheese sauce to a slight simmer, stirring constantly until it has thickened.

Add half of the cooked bacon pieces to the roasted broccoli and cauliflower. Pour the cheese sauce over the vegetables and top with the remaining shredded cheddar and parmesan cheese.

Bake the casserole for 20-25 minutes until the cheese has begun to brown on top.

Before serving, allow the casserole to rest 5-10 minutes to allow the cheese sauce to thicken, top with the remaining bacon pieces.