Al Pastor Tacos

0 Blend pineapple juice, tomato paste, garlic, onion, olive oil, vinegar, smoked paprika, chili flakes, salt, and pepper into a smooth marinade.
1 Coat pork and marinate at least 30 minutes (up to overnight).
2 Grill or sear pork 3–4 minutes per side until charred but juicy; rest 5 minutes, then slice thin against the grain.
3 Grill pineapple slices until caramelized.
4 Serve in warm tortillas with pork, pineapple, onion, cilantro, and lime.