Authentic Beef Barbacoa (Barbacoa de Res)

Place the brisket at the bottom of a stovetop pressure cooker. Add sliced onion, minced garlic, and bay leaves on top of the brisket; season with salt. Pour water over the ingredients to cover them completely, then close the cooker securely and attach a pressure regulator according to the manufacturer's guidelines. Continue heating until steam begins to escape in a steady flow, making a whistling sound, which should take around 10 minutes. Adjust the heat so that the regulator is gently swaying back and forth, indicating it's at the right temperature. Cook for 60 minutes.

Allow the pressure to release naturally, as instructed by the manufacturer, and wait for 5 to 10 minutes. Carefully unlock the lid of the pressure cooker and remove it from the pot. Take out the brisket and shred it using two forks.

Strain the cooking liquid to separate the solids from the liquid, discarding the solids. Measure out 2 cups of barbacoa sauce and set it aside for later use.

Combine guajillo chile peppers and ancho chile peppers in a saucepan. Add water to cover them, bring the mixture to a boil, and cook for 5 minutes. Remove from heat and let it sit in the hot water until softened, taking about 5 minutes. Drain the peppers.

Combine the softened chile peppers, vinegar, garlic, cloves, allspice, black pepper, oregano, thyme, cumin, ginger, cinnamon, and the reserved 2 cups of cooking liquid in a blender or food processor. Blend until the mixture is thick and very smooth.

Pour the sauce into a heavy-bottomed pot over medium heat, adding salt to taste. Bring the mixture to a soft boil; reduce the heat to low and stir occasionally. Add the shredded beef, coating it completely with the sauce. Cover the pot and cook until the flavors have combined, which should take at least 30 minutes and up to 1 hour.