Preheat your oven to 325°F (163°C).

Heat olive oil in a large Dutch oven over medium-high heat. Season the brisket generously with salt and pepper. Once the oil is hot, add the brisket and sear on all sides until browned, about 4-5 minutes per side. Remove the brisket and set aside.

In the same pot, add the chopped onion and sauté until softened, about 5 minutes. Stir in the roasted garlic and cook for an additional 2 minutes, until fragrant.

Add the fresh blackberries, red wine, beef bone broth, balsamic vinegar, brown sugar, Dijon mustard, thyme, and rosemary to the pot. Stir well to combine, scraping up any browned bits from the bottom of the pot.

Return the seared brisket to the pot, ensuring it is submerged in the liquid. Bring the mixture to a simmer, then cover with a lid and transfer to the preheated oven.

Braise the brisket in the oven for 3 to 4 hours, or until it is fork-tender and easily shreds.

Once the brisket is done, remove it from the pot and let it rest on a cutting board. Strain the braising liquid through a fine-mesh sieve into a saucepan, pressing down on the solids to extract all the juices. Bring the strained liquid to a simmer and reduce it until it thickens, about 10-15 minutes. Adjust seasoning with salt and pepper as needed.

Slice the brisket against the grain and serve it with the rich bone broth gravy drizzled over the top. Garnish with fresh blackberries and chopped parsley for a pop of color.