Preheat the oven to 550°F (or as hot as it goes). Trim brisket to a layer of fat about a 1/4 inch thick, then cut the meat into 4-5 inch cubes. Distribute meat evenly on a sheet tray with a wire rack and place in the preheated oven for 5-8 minutes or until evenly browned on all sides (turn as needed).
In a braiser or dutch oven, add canola oil and garlic and saute until browned. Add in onions and cook to caramelize lightly. Once onions are caramelized, add in ancho chile powder. stir to incorporate. Cook for 2 minutes. Add in tomato paste and cook for 5 minutes. Add in San Marzano tomatoes and cook for 4 minutes. Deglaze with half the beef stock. Bring to a simmer for 5 minutes while stirring, and then carefully pour your mixture into the blender. Blend until very smooth.
Place cinnamon, coriander, clove, cumin, peppercorns, oregano, bay leaf in the pot and pour blender mix over plus remaining beef stock. Bring to a simmer for 20 minutes.
Place meat in the pot making sure to nestle it in and cover with liquid. Wrap the pot with aluminum. Braise at 325°F for 3 hours. Pull the braise out of the oven and let it chill at room temp for an hour. Pick the meat free of any bone or cartilage.
Transfer the braising liquid into a pot and bring up to a simmer. Then strain and reserve. Take one cup of the braising liquid and add it into the mixing bowl. Using a fork or gloved hands, shred the meat until it is consistently broken down.
Line a prep area with plastic wrap and lay out your empanada wrappers. In the center of each wrapper, place about ¼ cup of the shredded beef braise and 2 tablespoons of the grated cheese. Fold the empanada to create a half moon and crimp the edges to form a seal. Ensure the two halves adhere to themselves. This step is very important, the empanada wrappers must be tightly sealed in order to fry correctly. The empanada wrappers are bought with a small plastic square separating each wrapper, you want to re-wrap each individual empanada with this plastic wrap for storage.
While the empanadas chill (at least 30 minutes), get your frying oil ready. Heat canola oil in a wok or heavy-bottomed pot leaving 4 inches of space from the lip of the pan. Heat oil to 365 degrees. Place 1 or 2 empanadas in the wok to fry at a time. Cook for about 5 minutes, turning once to brown on both sides.
Serve immediately with strained broth as a dipping sauce in a small ramekin. Garnish the dipping sauce with scallions and the empanadas with chopped cilantro.
