This is a recipe my mom and dad used to make in a slow cooker all of the time.  Over the years I have used the beef as a topping for taco salad or a filling for enchiladas or tacos.  If prepared well in advance you can skim the fat off of the flavorful juices and thicken it with masa flour.  Tonight, I'm trying this method on some tough old steaks that I wasn't too crazy about grilling.  This recipe also works with chicken thighs and pork butt.

In a small bowl mix together:
2 T Chili powder
1 TCocoa powder
1 T Salt
1 TCumin
Dash of chipotle chili powder (careful, it's spicy)
Black pepper
2 t Dried oregano
1 T Coriander seed
1 t Allspice

Place in a slow cooker or Dutch oven:
Beef roast, 3-4 pounds
Onion, sliced
4 Garlic cloves

Smear the roast, onions and garlic with 1 can of tomato paste.  Toss all with the spice rub.  Cook in a slow cooker or a very low oven until the beef is very tender.  Remove beef from pan and set aside to cool.  When cool enough to handle, shred beef between 2 forks.

For enchilada sauce:  Strain juices through a seive and skim as much fat off the top as possible.  Simmer juices in a sauce pan and thicken with masa flour.  Adjust seasonings.  Depending on my mood I might add a bit of hot sauce, green chilis, sour cream or cheese.  Stir a bit of sauce in with the beef to moisten it before making the enchiladas, then pour remaining sauce over all.