Step 1: Prepare Brisket - Take the brisket out of the refrigerator 30 minutes before cooking to ensure it cooks evenly. Rub the entire surface with olive oil, followed by an even coating of salt, black pepper, dried thyme, dried rosemary, garlic powder, and onion powder.

Step 2: Prep Aromatics - While the brisket sits, dice half of the yellow onion and thinly slice the other half. Mince the garlic and dice the shallot.

Step 3: Make Sauce - In a large skillet over medium heat, sauté the diced onion, shallot, and minced garlic for about 5-7 minutes until fragrant and translucent. Stir in the cranberry jelly, Worcestershire sauce, and Guinness, then simmer for about 10 minutes.

Step 4: Preheat Oven - Preheat your oven to 250°F (121°C).

Step 5: Assemble Dish - Pour half of the sauce into a roasting pan, scatter the onion, and place the brisket fat side down. Pour the remaining sauce over it.

Step 6: Add Sides - Arrange red potatoes around the brisket, sprinkle dried cranberries, and add fresh herbs. Cover tightly with foil.

Step 7: Roast - Roast in the preheated oven for approximately 4 hours until fork-tender.

Step 8: Rest and Serve - Let the brisket rest for 30 minutes before slicing. Serve with roasted potatoes and drizzle with sauce.