In a large skillet, heat the oil. Once hot, add the chuck roast pieces and cook until browned on all sides. Remove and place in the bottom of your slow cooker.

In the same skillet, whisk together the beef broth, tomato sauce, flour, chili powder, garlic powder, and bullion paste. Once combined, continue to cook, stirring often, until it starts to thicken, about 5 minutes.

Pour the mixture over the beef in the slow cooker.

Put the lid on the slow cooker and cook on low for about 4-5 hours, or until the beef pulls apart easily.

Once the meat is done cooking, remove it to a cutting board, reserving the sauce in the slow cooker. Shred the meat.

Preheat the oven to 350ºF. Spray a 9x13-inch casserole dish with nonstick cooking spray.

To assemble, place about 2 tablespoons of cheese down the center of each tortilla. Divide the beef evenly between the 6 burritos, then roll up by tucking in the sides of the tortilla, then fold the top over, rolling and tucking as you roll. Place the burritos in the prepared casserole dish, seam side down.

Take as much of the sauce as desired and pour over the top of the burritos. (I like to make sure all of the burritos are covered, and then will reserve the rest of the sauce for serving.) Top with the remaining cheese.

Place in the oven and bake until the cheese is melted, about 15 minutes.

Serve the burritos topped with minced cilantro, if desired.