I love Carnitas but my husband has trouble eating pork (gives him migraines) so I looked around for recipes using beef. I used several to come up with my own recipe. It was quite the hit with my family.
Rub chuck roast with garlic olive oil. Place on large piece of heavy duty aluminum foil.
Sprinkle both sides of roast with cumin, salt and pepper (pat to help it adhere to the meat). Mix green chilies and jalapenos together. Spread on both sides of roast. Scatter with onions. (I chose to put it in a gallon zipper bag and let it sit in the fridge over night, but you don't have to if you don't want).
Wrap the roast tightly with the foil and place in slow cooker. No liquid is needed.
Cook on low for approximately 8 – 10 hours.
Remove from the slow cooker. Unwrap foil and allow roast to cool for a few minutes. Drain liquid into a separate bowl (reserve). Scrape chilies and onions off the roast. Using two forks (or if cool enough, use your fingers) and shred the roast.
Heat garlic olive oil in a large skillet. Sear the roast in the skillet. This gives the meat its signature crust. Return some of the liquid (minus any fat) to the meat.
Serve with your favorite sides (rice, re-fried beans, sour cream…), make tacos or burritos.