I need a slow cooked beef recipe that would be great taco filling
Picadillo, which you could do in a slow cooker but is OK in a skillet. Brown ground sirloin with chopped onion and green pepper. Add a handful of raisins and some green olives stuffed with pimiento. Add an 8-oz can of tomato sauce and a can of water and season with salt, garlic, and cumin (don't even think of omitting the cumin). Let it cook for a bit. Serve with rice or makes a good taco filling or fills any hollowed-out vegetable.
My Salvadorean brother-in-law makes a killer boliche, as follows:
He uses bottom round, about a 10-12 lb. roast. Poke slits in the meat with a sharp knife and insert whole cloves of garlic about an inch deep. Rub the roast with olive oil and cover with adobo, black pepper and powdered garlic. Roast it 425 degrees for half an hour to 45 minutes in an uncovered dutch oven until it's nice and brown. Remove from the oven, add crushed tomatoes, green olives, raisins and red wine. Cover tightly and reduce the oven temperature to 200 degrees. Let it cook all night.
It is fantastic! Serve it with steamed white corn tortillas or hard rolls.
Try as search on 'deshebrada', shredded, to get recipes like this:
Any good braising cut can be cooked till tender in a lightly flavored broth, shredded, and served with a spicier chile sauce.
A traditional beef preparation in northern Mexico (machaca), starts with air dried beef (jerky).
Unfortunately I cannot personally vouch for either of these recipes, but I've had them bookmarked for a while and both have rave reviews from others:
Edited: I misread your original post and thought you meant "slow cooker" recipes. Do you have a slow cooker, or were you planning on, say, braising in a Dutch oven?
I made something like Ropa Vieja for the first time about a month ago when chuck roast was on sale. It was delicious and would be great in tacos.
I used a 3lb Chuck Roast. Rubbed about 2t ea salt & pepper into it and browned in a Hot cast iron skillet w 2T oil about 2-3min per side; transfer to Crock Pot. Thinly slice 1 large or 2 small onions; a bell pepper, chop garlic (I used 6-8 cloves). Seed and chop chili peppers - I used 1 jalapeño & 2 Serrano. Add vegetables, 2 cans diced tomatoes, and 1/2t cumin to top of roast. Cook on low until meat is tender - we went 7 hrs. Remove the roast; pull away & discard fat & connective tissue; shred with forks. Combine shredded beef and veggie mixture and serve.
I make the recipe in the link below and just eat it on a plate with beans, rice, and tortillas on the side. My son will wrap it up in his tortilla and eat it like a taco.
The extra benefit of this recipe is that you are left with a wonderful beef stock when you are done cooking. Do not throw it out.