1. Preheat sous vide to 130 degrees Fahrenheit.
2. Place roast in a gallon-sized freezer Ziploc bag. Drizzle with olive oil and add a few whole sprigs of fresh rosemary and thyme to the bag. Seal bag most of the way, then slowly lower it into the water bath to force the air out. Seal bag the rest of the way and cook for 12 hours.
3. When roast is done, transfer it to a sheet pan and pat dry with paper towel. Sprinkle with salt.
4. Preheat oven to 400 degrees Fahrenheit.
5. Finely chop remaining rosemary and thyme, then combine with margarine or Earth Balance, salt, and pepper.
6. Wearing gloves, rub herb mixture all over the roast until completely covered.
7. Set the roast in a shallow roasting pan along with vine tomatoes. Roast for 20 to 25 minutes, or until a nice crust has formed. Transfer roast to a cutting board and let it rest for 20 minutes.
8. Reduce oven temperature to 350 degrees Fahrenheit, then return the baking sheet with the tomatoes to the oven to cook for another 10 minutes, or until soft.
9. Slice roast thinly. Serve with roasted tomatoes.
Variations: Oven Method: Season roast with salt, then sear in a large skillet until a nice crust has formed. Coat with Earth Balance-herb mixture, then roast at 400 degrees Fahrenheit until an internal thermometer reads 130 to 135 degrees Fahrenheit, about 40 minutes. Let rest for 20 minutes before slicing.