The Best Steak Fajitas

Combine all the ingredients in a small bowl. Store in an airtight container for up to 6 months

In a shallow bowl, combine the garlic, fajita seasoning, ¼ cup olive oil, and cilantro. Toss the steak to coat in the marinade, cover and marinate for 30 minutes

Meanwhile, heat a 12-inch cast-iron skillet over medium-high heat. Place the butter, 1 tablespoon olive oil, and onion in the skillet. Season with the salt, stir, and cook until the edges of the onion are deeply golden yet still a bit firm, about 10 minutes

Add the peppers and cook for 5 to 8 minutes more, depending on how done you prefer them. Transfer the onion and peppers to a small dish

Working in two batches, sear the steak on both sides for 3 to 4 minutes on each side. Transfer to a cutting board and let rest for 5 to 8 minutes before slicing into thin strips

Return the strips and any juices from the cutting board to the skillet, squeeze in the juice from the lime wedges, and cook for 3 to 4 minutes more. Remove from the heat and tent with aluminum foil to keep warm

Serve on warm tortillas. Garnish with smashed avocado that's been mixed with a sprinkle of kosher salt and a squeeze of fresh lime juice. Top with Cotija cheese and more cilantro if desired