Prepare the Beef:
Place the beef chuck roast in a large pot or Dutch oven, covering it with water. Simmer over medium-high heat for 2-3 hours, or until the beef is fork-tender. Once done, remove the beef and shred it using two forks.

Make the Sauce:
In the same pot, heat some oil and sauté garlic and onion over medium heat for 3-4 minutes. Add the Hatch Chile Colorado sauce and beef bouillon granules, then return the shredded beef to the pot, stirring to combine.

Thicken the Sauce:
In a small bowl, whisk together the heavy cream, flour, and water. Add this mixture to the pot and stir well. Simmer for 5-10 minutes, until the sauce thickens and coats the beef.

Assemble the Burritos:
Warm the flour tortillas in a dry skillet for about 30 seconds per side. Once warmed, spoon a generous amount of the beef mixture onto the center of each tortilla. Top with Monterrey Jack cheese and fresh cilantro.

Roll the Burritos:
Fold in the sides of the tortilla, then roll it tightly to secure the filling. Repeat with the remaining tortillas.

Serve:
Serve the burritos with optional toppings like sour cream, pico de gallo, and guacamole. Enjoy!