Grilled Skirt Steak Fajitas Recipe

Name: Grilled Skirt Steak Fajitas Recipe
Ingredients: 1/2 cup (120ml) soy sauce; 1/2 cup (120ml) lime juice, from 6 to 8 limes; 1/2 cup (120ml) canola oil; 1/4 cup (55g) packed brown sugar; 1 tablespoon chili powder (see note); 3 medium cloves garlic, finely minced (about 1 tablespoon); 2 teaspoons ground cumin seed; 2 teaspoons freshly ground black pepper; 2 pounds (900g) trimmed skirt steak (about 1 whole steak; see note), cut crosswise into 5- to 6-inch pieces; 1 large red bell pepper, stemmed, seeded, and cut into 1/2-inch-wide strips; 1 large yellow bell pepper, stemmed, seeded, and cut into 1/2-inch-wide strips; 1 large green bell pepper, stemmed, seeded, and cut into 1/2-inch-wide strips; 1 white or yellow onion, cut into 1/2-inch slices; 12 to 16 fresh flour or corn tortillas, hot; 1 recipe guacamole, for serving, if desired; 1 recipe pico de gallo, for serving, if desired; Sour cream, shredded cheese, and salsa, for serving, if desired