Rub the brisket on all sides with the sea salt, black pepper, and rosemary.

(Note, the following step is recommended for best flavor, but is optional. If preferred, move on to the next step without searing the meat.) In a large skillet, heat the olive oil over medium high heat. Sear the brisket for 3 to 4 minutes on each side.

Transfer the brisket to a 4- to 6-quart slow cooker. Spread the tomato paste evenly over the brisket. Arrange the onions, garlic, and carrots around the brisket. Cover and cook on LOW for 7 hours or until the brisket is fork tender.

Slice the brisket and arrange the slices on a platter. Serve with the cooked onions and carrots.

Season with additional sea salt and black pepper to taste and garnish with the parsley.