In a saucepan or small dutch oven, melt the tablespoon of butter and add onions and garlic to the pan. When the onions and garlic begin to brown and become translucent, add heavy whipping cream.
As the onions and garlic saute, steam the fresh spinach in a microwave steamer for three minutes. When done, squeeze the excess water from the spinach.
Continue to stir the cream and onion mixture as you add the steamed spinach and cheeses to the pan. Only use 1/4 cup of the parmesan in the spinach dish. Season with the salt and pepper.
When cheese is completely melted, add the remaining parmesan cheese to the top of the keto creamed spinach. Place pan under the oven broiler until cheese melts and browns.