Preparing the Sauce

Cup of Yum
1. In a medium-sized saucepan, melt the unsalted butter over medium heat.
2. Once the butter has melted, add the all-purpose flour and whisk continuously for about a minute to create a roux. 
3. Slowly and gradually pour in the chicken stock or beef stock while whisking vigorously to prevent any lumps from forming. 
4. Stir in the red enchilada sauce, add the salt, and allow it to simmer for a few minutes until the sauce thickens. Set aside.

Cooking the Beef Filling

1. Heat the olive oil in a large skillet over medium heat. 
2. When hot, add the ground beef and cook until it's browned and fully cooked through.
3. Stir in the diced onion and chopped green chili. Sauté until onions are translucent.
4. Add the taco seasoning and give them a good mix. Remove from heat and set aside.

Assembling and Rolling the Burritos

1. Preheat the oven to 180℃ (360℉).
2. Warm the tortillas slightly to make them pliable. Place a tortilla on a clean surface.
3. Spread some of the beef filling mixture in the center.
4. Top the beef filling with a scoop of black beans followed by a spoonful of Mexican rice.
5. Sprinkle a little shredded mozzarella and chopped fresh coriander leaves on top.
6. Fold the sides of the tortilla over the filling, then roll it up tightly from the bottom to create a burrito.
7. Continue the process until you have used all the filling ingredients. 

Cooking and Serving

1. Place the prepared wet burritos seam-side down in an oven-safe dish.
2. Bake the burritos for 15 minutes, then remove them from the oven.
3. Pour the sauce over the burritos, spread the remaining shredded cheese, and bake for an additional 20 minutes, until the cheese is melted and bubbly.
4. Once baked, remove them from the oven and let them cool slightly before serving.