1 cup Orange juice (whatever you have in your fridge is fine)
1 Lime, zested and juiced
3 tbsp Garlic, minced
1 tbsp Ground cumin
1 tsp Kosher salt
1½ – 2 lb. Flank steak
2-4 Bell Peppers, thinly sliced
1-2 Onions, thinly sliced
Optional toppings – sour cream, shredded cheese, guacamole, etc.
To make the marinade in a food processor, first add the chilis or cilantro and pulse until they are minced and have a paste-like consistency. You can also easily make this marinade with one bowl and a whisk, chopping the chilis and cilantro first.
Add canola oil, orange juice, lime, garlic, cumin and Kosher salt to the processor and pulse to combine.
Score the flank steak (make diagonal cuts about 1/4 inch deep all the way across in both directions, making a diamond pattern) and slice the steak into three pieces against the grain (if the meat is laying in a rectangle in front of you, against the grain would be top to bottom). Place all three pieces of steak in a zip-top bag and add marinade, reserving 1 cup for the vegetables. After sealing the bag, make sure the flank steak is completely covered.
Marinate at least 2 hours and up to overnight, refrigerated. Refrigerate the marinade for the veggies separately.
Preheat oven to 450 and move top rack to the uppermost level in the oven. Take the steak out of the fridge so it can start to come to room temperature.
Toss vegetables in the reserved marinade. Line a rimmed baking sheet with aluminum foil. Place vegetables on the baking sheet and spread evenly, so that each piece is touching the baking tray and not touching each other (this helps them to caramelize and prevents steaming).
Roast for 15 minutes. Remove tray from the oven, evenly divide the peppers and onions and move them to the two end of the tray (they will be in heaps at this point and that’s what you want), clearing a space for the flank steak. Add the steak to the tray.
Increase oven temperature to broil. Broil for 5 minutes. Remove tray from the oven and place vegetables in a bowl and cover with foil. Flip flank steak pieces and return to the oven. Broil for 5 minutes.
Remove tray from the oven and place flank steak pieces on a cutting board fitted inside a rimmed baking sheet (makes for easier cleanup). Let steak rest for 10 minutes uncovered. Thinly slice against the grain and enjoy in tortillas with the vegetables and your choice of toppings — cheese, salsa, guacamole, sour cream or whatever you like!