pot roast, I finally got it right!

From Tara's Kitchen:

Pot Roast
I used a Diet Coke and it was fantabulous!

Ingredients
• 1 (4 lb) top sirloin roast
• whole garlic clove
• 1 teaspoon fresh ground black pepper (or to taste)
• 5 carrots, chopped into large chunks
• 6 large potatoes (or as many as you like)
• 1 large onion, sliced (optional)
• 2-3 tablespoons fresh minced garlic (optional)
• 1 (3/4 ounce) package brown gravy mix (I suggest to use low-sodium)
• 1/2 cup water or beer
• 2-3 tablespoons worcestershire sauce
• 1 (1 ounce) package dry onion soup mix
• 1 (10 ounce) can cream of mushroom soup, undiluted
• 2 tablespoons fresh minced garlic (optional or to taste)
• 1 (10 ounce) can cola, beverage (Coca Cola is the best for this)
Directions
1. Set oven to 350 degrees F (will reduce oven temperature later).
2. Make small slits all over the roast then insert a garlic clove in each slit (make as many slits and use as many cloves as desired).
3. Season the roast with black pepper.
4. Grease a roasting pan.
5. Layer the sliced onions (if using) and garlic into the bottom of the pan, then place the roast on top.
6. In a medium bowl combine the brown gravy mix with water mixing into a smooth paste, then add in the onion soup mix, mushroom soup, minced garlic, cola beverage and Worcestershire sauce; mix well to combine.
7. Pour the cola mixture over the roast.
8. Cover and cook at 350 degrees F for about 1 hour.
9. Uncover and place the carrots and potatoes around the roast.
10. Reduce the oven temperature to 275 degrees F and continue cooking covered for another 2 hours.
11. Remove from oven and turn the roast over, place back in oven for another 1-2 hours or until roast is tender (could take longer than 2 hours, as you are cooking at a low temperature).
12. Let the roast stand for 20 minutes before slicing.