Preheat your oven to 300°F and set your dutch oven over medium heat on the stove.
Season the brisket liberally with salt and pepper on both sides. Place fat side down in the hot dutch oven and allow to sear until a deep golden brown, 6 to 7 minutes.
Remove the brisket from the pan and turn off the heat. Take a few minutes to quarter your onions, thinly slice your garlic, and to create a bundle with the herbs by tying with string or cheesecloth.
Once the pan has cooled slightly, add in one tablespoon of butter and stir to melt.
Once melted, add in the two tablespoons of flour and stir to create a paste. Continue stirring letting the residual heat from the pan cook the paste until golden brown. If your pan has cooled too much, turn heat back on to low.
Remove the golden brown roux from your pan and store it in a small bowl for later, covering and refrigerating once cool.
Wipe the pan clean of any excess roux and return the pan to medium heat, adding in the remaining two tablespoons of butter.
When butter has melted, add in quartered onions and allow to caramelize, 5 minutes or so.
Add the tomato paste and garlic to the pot and stir, letting it cook until fragrant, about 1 minute.
Pour in the wine and beef stock and bring to a boil. Once boiling set your brisket, fat side up into the liquid, keeping the top half above the liquid level. Use the onions to prop it up if necessary.
Cover and place in the oven for 3 ½ hours.
Remove from the oven carefully and lift out the brisket, onions, and herb bundle. Discard the onions and herbs.
Place the braising liquid over medium heat and get the roux out of the fridge. Add it in, stirring constantly until completely dissolved. 1 to 2 minutes.
Cook, stirring occasionally, until it comes to a boil at which point it will thicken, the pan is still hot, so this takes just another 2 minutes or so.
Slice the brisket and serve with a hearty pour of sauce.
If you've tried this recipe, come back and let us know how it was in the comments or ratings!