Preheat the oven to 325 degrees F.
Combine the garlic, salt, and thyme with 2 tablespoons of olive oil and stir to combine.
Generously season both sides of roast with kosher salt and black pepper. Place a large Dutch oven over medium-high heat and coat with the remaining olive oil. Place the Roast in the dutch oven and sear for 4-5 minutes on both sides until golden.
Place the onions into the dutch oven around the brisket and brush the thyme and garlic mixture over the top of the roast. Add the wine, tomatoes, parsley, and bay leaves. Cover and transfer to the oven. Bake for about 3 to 4 hours, basting occasionally until fork tender.
Carefully remove the roast to a cutting board and let it cool before slicing.
Boil and stir the remaining sauce for 5 minutes until the sauce reduces by ½ and thickens.
Slice the roast against the grain, transfer to the platter with the onions and pour the sauce on top.