Mexican is so easy to get 'wrong'. Take, for example, about 95% of Mexican restaurants in the U.S. - you can't tell what you're eating because it's slathered in red sauce and cheese. The best Mexican I've ever had (not having lived close to Mexico and having somewhat limited exposure) was at Taco Roc. Story goes that the guy who started Taco Roc couldn't find any Mexican restaurants he liked either, so he started his own restaurant. I'm glad he did. Inexpensive, flavorful, and friendly. (Their agua fresca is awesome!) My favorite is their Al Pastor, a spicy marinated pork with chilies and pineapple. In fact, I liked it so much, I went in search of a recipe so I could recreate it at home. Unfortunately, like many good recipes, there are as many versions as cooks. So, here is my version that I came up with after reviewing quite a few recipes online. Taco Roc makes theirs with ancho chiles, but when I tried them, the Al Pastor didn't have much flavor. So, I'll stick to guajillo chilies.
Oh, you can use this stuff in/on anything: burritos, tacos, nachos, pizza...pretty much anything you can think of. Yum.
~4 lb bone-in pork roast
1 medium yellow onion, chopped
1 1/2 tsp. minced garlic
1/4 tsp. ground cumin
1/2 tsp. dried oregano
2 Tbsp. canola oil
1 small can pineapple chunks, drained - reserve juice ( or 4 rings)
13 dried guajillo chiles, soaked, seeded, stemmed
In a crock pot, cook the pork roast in a few cups of water overnight (or during the day). Remove the roast from the crock pot, and when cool enough to handle, shred the meat.*
In a blender or food processor, pulse the garlic, cumin, oregano, oil, pineapple juice, and peppers until mostly smooth. You can also add the pineapple if you don't want bigger chunks in with the meat. Add the chunks of pineapple and the sauce to the shredded cooked pork and simmer about 20 minutes. Let it sit overnight and reheat in a skillet.
*I've also read that you can cube/dice the pork and then cook it in the crock pot with the sauce. However, I think shredding the meat first allows for more even coating and consistent flavor.