Preheat the oven to 375F. Grease a 9-inch casserole dish with cooking spray and keep it ready.
In a saucepan; boil some water with salt. Add the cauliflower florets and cook for 5 minutes until the cauliflower turns tender. Drain the water and keep the cauliflower aside.
To the same saucepan add the heavy cream and once the cream starts boiling add the cream cheese. Cook until the cheese is melted.
Reduce the flame low and add 1 cup of cheddar cheese to the saucepan and allow the cheese to melt completely. And then add in the spices; garlic powder, parsley, ground mustard, ground pepper, and salt.
To the prepared cheese sauce add the cooked cauliflower and coat well and transfer it to the prepared casserole dish.
Add a layer of remaining cheddar cheese on top of the cauliflower.
In a small bowl, combine almond flour, parmesan cheese, melted butter, parsley, and salt. Add this crunchy topping over the cheddar cheese layer.
Bake until the cheese has completely melted for 18-20 minutes.
Serve the keto mac and cheese while it is still warm.