Trim the beef chuck roast of excess fat and season all sides with sea salt and black pepper.
Heat olive oil in a heavy-bottomed pot over medium-high heat and sear the beef until a deep golden crust forms on all sides.
Remove the beef and set aside; in the same pot, sauté the diced onion, carrots, and celery until they begin to soften.
Stir in the minced garlic and tomato paste, cooking for one minute until fragrant.
Pour in the red wine to deglaze the pan, scraping up all the brown bits from the bottom.
Return the beef to the pot, add the beef broth, thyme, and rosemary, then cover and simmer on low for 2-3 hours until tender.
While the beef rests, steam the cauliflower florets until soft, then mash with ghee and a pinch of salt.
Serve the braised beef and vegetables over the cauliflower mash, drizzling with the remaining pan sauce from the pot.