Tender beef tri-tip is marinated in a spicy, deeply flavored chili mixture. It’s then grilled over high heat and thinly cut for tacos with slices of avocado and a chopped onion and cilantro mixture, typical of street tacos.
Add the guajillo chilies and chiles de arbol to a medium bowl and pour hot water over the top, letting it sit until the chilies soften, about 10 minutes.
Add the softened chilies and ¾ cup of the soaking water to a blender with the chipotle and adobo sauce, onion, garlic, orange juice, lime juice and oregano. Blend until smooth, then season to taste with salt.
Add the Swift Meats beef tri-tip to a large bowl or resealable container and pour the marinade over the top, turning to coat. Cover and refrigerate for at least an hour or up to overnight.
When ready to grill, remove the meat from the marinade, wiping off any excess marinade. Heat the gas grill to medium-high.
Add the tri-tip and sear for about 8 minutes. Turn the meat over and cook for an additional 8 minutes. Turn and cook once more for another 5 minutes. Repeat until a thermometer inserted into the thickest part of the meat reads 130ºF. A 2-pound tri-tip should take a total of about 25 minutes to cook.
Remove the meat from the grill and let rest on a cutting board for 15 minutes.
Thinly slice the meat and set aside on a serving platter.
In a small bowl, stir to combine the onion, cilantro, serrano and lime juice. Season to taste with salt.
To assemble the tacos, lay slices of the steak onto the tortillas and top with avocado and a spoonful of the onion mixture. Serve immediately.