Cook both bags of cauliflower rice per the package instructions. Drain the excess water from the bags then set aside.
Melt the butter in a sauté pan over medium heat. Add the mushrooms and onions, and sauté for about 10 to 15 minutes until the onions are translucent and browned and the mushrooms are soft and browned. Cook enough to allow liquid to evaporate.
Add the minced garlic and thyme. Sauté for about 1 minute until fragrant.
Add Worcestershire sauce, salt, and pepper. Sauté for about 1 minute.
Add both bags of drained cauliflower rice. Increase heat, then sauté until excess liquid is evaporated.
Reduce heat to low. Stir in the cream and parmesan cheese. Continue to heat, stirring constantly, for about a minute until the cheese melts and sauce is smooth. Season with additional sea salt and black pepper to taste.