Sear brisket on all sides.
Season the brisket with about 2 tsp. salt and pepper, or to taste. Heat grapeseed oil (or oil of choice) in the pot or dutch oven over medium-high heat and add brisket. Brown on all sides. Remove from dutch oven and set aside.
Sweat onions, add herbs and braise, 3 hrs.
Preheat oven to 375°F (190°C). In the same dutch oven, add the onions and sweat it out a bit, stirring, around 10 minutes or so. Add the fresh thyme, parsley, dried bay leaves, and tomato paste. Stir around for a while, about 2 minutes. Add meat back into dutch oven along with the beef broth and red wine. Cover and braise in oven for 3 hours.
Begin caramelizing onions 2 hours in.
2 hours into braising the brisket, begin caramelizing your onions. Put a small pot over medium heat with a dollop of olive oil and sauté for a couple of minutes. Add cloves and star anise. Turn down to low heat and continue to cook onions, slowly caramelizing. It will take about 45 minutes for the onions to caramelize. Keep watch and stir once in a while so that the onions don’t burn on the bottom of the pot. When the onions are ready. They’ll be a deep brown colour. Salt to taste.
Remove brisket from oven and rest.
After 3 hours of braising, check on the brisket. It should be very tender. Remove from oven and let it rest on a chopping board. Keep the braising liquids but discard the solids.
Remove spices from onion, add flour.
After about 45 minutes of cooking, your onions should be caramelized. Remove the cloves and star anise from the mixture. The onions are now ready to be turned into a gravy. Turn heat to medium and add flour to the onions, stirring until well coated. Add butter and stir a little more.
Whisk in braising juices to onion mixture.
Whisk in some of the braising juices to the onion mixture. Start with 1 cup and continue whisking. As the mixture comes to a boil, the gravy will begin to thicken. Add more braising juices to thin down the mixture to your liking. Whisk until the gravy is smooth and salt and pepper to taste. Set aside for serving.
Boil cauliflower in cream.
In another pot, bring the half and half to a boil and add cauliflower and butter. Cook the cauliflower until soft and the half and half has reduced about a half, about 10-15 minutes.
Blend cauliflower into purée.
Take the cauliflower and half and half mixture and pour into a food processor. Blend on high for about 5 minutes or until the mixture is smooth and. Salt to taste. You are now done with all the components and ready to assemble! Spoon some of the cauliflower purée onto the center of a plate. Slice the rested brisket and place on top of cauliflower purée. Spoon the onion gravy over the meat, garnish with chopped parsley and serve. Congrats! You just made red wine braised brisket with onion gravy and cauliflower purée.