In a large pan over medium heat, fry the garlic and onion in butter until they become soft. Put a side
Increase the heat to medium-high and stir fry the meat for a couple of minutes on each side until lightly browned and seared.
Add onion, tomato paste, Dijon mustard, paprika, thyme, and water.
Let simmer on low heat until the meat is tender, approximately 1 hour. Add salt and pepper to taste.
After 1 hour, add heavy cream and let simmer for 10 more minutes.
In a large frying pan on medium-high heat, add butter.
When hot, add the cauliflower and fry until softened. Season with salt to taste.
Top with some parsley on top.
Serve the beef Stroganoff together with the cauliflower rice and lettuce (optional).