01 -
To a large cast-iron skillet over medium-high heat, add oil. Once the oil is hot, add the chuck roast to the skillet and sear on each side, just enough to brown (3-5 minutes per side).
02 -
Add the seared beef to a crockpot. Top with bouillon powder and the enchilada sauce. Cover and slow cook on low for 10 hours, or until the meat is tender and easily pulls apart.
03 -
When ready, remove the chuck roast from the slow cooker and use two forks to shred. Add the shredded roast back to the juices in the slow cooker.
04 -
Preheat a skillet to medium-high heat. Butter one side of each slice of bread.
05 -
Working one or two at a time, add bread, buttered side down into the skillet. While it is cooking, top with ½ cup shredded beef, about 1 tablespoon of white onions, ¼ cup queso fresco, ¼ cup mozzarella, cilantro, and another slice of bread, buttered side up.
06 -
Cook over medium-low heat for 5-7 minutes; then, flip over the sandwich and cook another 5-7 minutes, or until golden brown. (If it seems like the bread is taking a long time to brown, be patient, as the cheese inside needs time to melt.) Use a spatula to remove from the skillet.
07 -
Serve with leftover juices from the slow cooker for dipping.