Step 1

With the rack in the middle position, preheat the oven to 180 °C (350 °F).

Step 2

Untie the roast and remove as mush fat as possible. Cut into five pieces.

Step 3

In an ovenproof pan, combine all the ingredients and bring to a boil. Cover and bake for about 3 hours or until the meat is very tender and falls apart with a fork. Season with salt and pepper.

Step 4

With a fork, shred the meat. Adjust the seasoning. Keep warm.

Step 5

In a bowl, combine all the ingredients. Season with salt and pepper. Let stand for about 10 minutes. Drain.

Step 6

Fill the shells with the meat mixture, lettuce, tomato salsa, sour cream, and cheese.