After managing to drag myself out of bed by 3:00 on Sunday (post-Halloween/birthday party), I got to cooking up this meal including mashed cauliflower, gravy, and cut up veggies/dip from the party. It was a total hit. Here's what I did for the brisket and gravy:
Pre-heat oven to 325*. Season brisket on both sides with oregano, salt, and pepper. Place in large oven safe pan. Sear both sides for 3 minutes on medium/high heat. Add remaining ingredients, cover, place in oven for 2.5 hours.
Remove from oven and put the meat on a plate or cutting board. Using an immersion blender, purée the veggies and drippings into a gravy.
Slice meat against the grain and serve topped with gravy.