Mexican Food Week continues with this question: A take-out taco stand in a food court within a third-rate shopping mall in a Boston suburb? That’s what I thought when my new friend Erika (a Mexico City native I met recently when we were both students in an Arabic-Syrian cooking class) told me that this place had the best carnitas tacos she’d found in New England. She added, “I know, I know...” and then assured me I would not be disappointed. I wasn’t. Trini’s Mexican Grill is a small, family-run storefront serving up tacos, burritos, quesadillas, etc. alongside some other sad vendors in this downscale mall. But Trini’s food is first-class. I decided to give it a try: tacos de carnitas and tacos al pastor, both exceptionally good. There’s a small condiments array from which you can serve yourself pico de gallo, jalapeños, guacamole, hot salsa, salsa verde and a few other selections. Three tacos (all with the same filling) $6.99. Add rice and beans for $1. Individual tacos $2.50. The people who work there (also from Mexico City) are really, really nice. And they’ll patiently practice your Spanish with you if you ask. I’ll be returning.