Lightly grease a slow cooker.
Cut roast into 3-4 chunks and add to slow cooker with chile Colorado, bouillon granules, garlic, and onion.
Cover and cook on low for 6-8 hours, or until meat is tender.
Remove meat from slow cooker (leave sauce) and shred with two forks. Season with salt and pepper, to taste. Set aside.
Preheat oven to 400 degrees Fahrenheit.
Lightly grease a 9×13 inch baking dish. Spread ⅓ cup of the sauce from the slow cooker in the bottom of the dish.
Place 1 ½ cups of the sauce from the slow cooker into a medium saucepan. Whisk in cream. In a small bowl, whisk together flour and water, then whisk the mixture into the sauce. Bring to a simmer over medium heat and season with salt and pepper, to taste. Simmer while preparing the burritos.
Divide the shredded beef evenly between the tortillas. Roll up and place seam side down in the prepared baking dish.
Pour the sauce over the burritos. Sprinkle with the shredded cheese.
Bake uncovered for about 20 minutes, or until cheese is melted and sauce begins to bubble.
Sprinkle with cilantro before serving. Serve with sour cream, pico de gallo, and guacamole, if desired.
