This is what I usually use for the filling of tamales. I tried to replicate the flavor and texture from the tamales that aunt Paty makes. You can eat the leftovers with beans and tortillas too.

1. Dice the meat into medium-small cubes
2. Place the diced meat in a large pan and put enough water to cover the meat. Add garlic and about 1 spoon of salt. Cook at medium-high heat
3. When the meat starts boiling, remove the grey foam that starts forming
4. While the meat is cooking, seed the peppers and let them rest in warn water for about 10-15 minutes.
5. Roast the tomatillos in a comal or griddle till they change color to darker green
6. Blend roasted tomatillos and peppers for about 45 seconds. Depending on your blender you might need to strain the sauce after blending.
7. By this time, the boiling water in the meat pan will be almost completely evaporated. Once it evaporates, you can sear the meat on the fat that rendered naturally from the meet. If there is no enough fat, you can add a little bit of oil. Continue browning the meat for about 3-5 minutes, stirring constantly, and making sure nothing burns.
8. Add the guajillo sauce and still. You might need to add a little bit of water if the sauce is too thick.