Prep time: 30 minutes
Total time: 1 hour 45 minutes (1 hour resting)
1/4 cup fresh lime juice
3 Tbsp olive oil, divided 2 Tbsp soy sauce
4 tsp dark brown sugar
2 cloves fresh garlic, minced, divided
2 tsp finely chopped fresh cilantro
1/2 tsp ground cumin
1 lb skirt steak, cut crosswise into 3 to 4 pieces
8 (8-inch) flour tortillas
1 large red onion, thinly sliced
1 large red bell pepper, cored, seeded, and sliced in 1/3-inch strips
1 large yellow bell pepper, cored, seeded, and sliced in 1/3-inch strips
3/4 tsp salt, divided
1/4 tsp black pepper
Optional toppings: salsa, sour cream, sliced avocado or guacamole, lime wedges
Whisk together the lime juice, 2 tbsp olive oil, soy sauce, brown sugar, half the garlic, cilantro, and cumin. Pour into a zip-lock bag, add the steak, and marinate at room temperature 1 hour, turning the bag occasionally.
Preheat oven to 325°F. Wrap stacked tortillas tightly in foil; warm for 15 minutes.
Heat a grill or grill pan to medium-high (or, alternately, heat the broiler). Remove steak from the marinade, and let excess drip off. Season with 1/4 tsp each of the salt and pepper. Grill (or broil on highest rack) to desired doneness (about 3 minutes per side for medium-rare). Transfer steak to a cutting board, tent with foil, and let rest 5 to 10 minutes.
While steak is grilling, heat a large skillet over medium-high heat. Add the remaining 1 tbsp olive oil and the sliced onion and peppers. Sauté, stirring often, 10 to 12 minutes, or until lightly charred. Add the remaining garlic in the final minute. Season with the remaining 1/2 tsp salt.
Thinly slice steak on the diagonal, across the grain. Transfer to one side of a serving platter and pile the veggie mixture on the other side. Arrange the toppings in small bowls, wrap the tortillas in a soft towel, and let everyone make their own fajitas right at the table. Serve with black beans and rice.