These flat-iron steak tacos are a flavorful way to spice up your dinner routine. These tender, juicy steaks are marinated in a zesty mixture and pair perfectly with the fresh toppings and warm tortillas. Whether you’re looking for a quick weeknight meal or a delicious dish for your next gathering, these tacos are sure to satisfy!
If you’re a fan of tacos, you’ll absolutely love these flat iron steak tacos. To make them, marinate the steak in a delicious Aji (green sauce) mixture and then grill it hot and fast. You can use flat iron steaks or substitute with any flat steak such as flank, hanger, skirt, or sirloin flap steaks.
What is Aji?
Aji is a South American sauce used widely in Columbia and Peru. This sauce (or chunky salsa) can range from mild to spicy, depending on the region and preference. It typically contains chili peppers, fresh herbs, garlic, onion, and citrus juice.
We’ll be using the milder version to marinate the flat iron steaks for this recipe. However, we recommend that you make a double batch of the aji mixture for these flat-iron steak tacos. Use half for the marinade, and reserve the other half to use as a topping for the tacos. Store it in an airtight container in the refrigerator until it’s time to use.
- Flat iron steak, 2 pounds (or flat steak of choice)
- Corn tortillas
- Toppings: Lettuce, guacamole, queso, pico de gallo, cotija cheese, etc.
- Small onion
- Cilantro: sub with flat-leaf parsley
- Olive oil
- Salt and black pepper
How to make Flat Iron Steak Tacos:
- Marinade for flat iron tacos: Pulse marinade ingredients in a food processor. Add more lime juice or oil as needed.
- Place the flat iron steaks in a resealable plastic bag. Pour the aji marinade over the steaks and work it to get an even coating. Seal the bag and place it into the refrigerator for 6-24 hours.
- Preheat your grill for medium-high heat, or 375 degrees F. Have a reliable instant-read thermometer handy.
- Place the marinated flat iron steak onto the grill. Cook 5-7 minutes per side. See our steak temperature guide to determine doneness.
- Wrap the tortillas in a large piece of aluminum foil. Place the packet on the grill for 5 minutes, turning once. You can also lightly toast them on by oen if preferred.
- Remove steak from the grill and set it onto a clean cutting board. Let it rest for 7-10 minutes.
- Build your flat iron steak tacos: slice steak into thin (1/4″) strips and serve in warmed tortillas along with your favorite toppings.
- If you’ve made a double batch of the aji sauce, use the reserved half to serve with the tacos.
- Meat: If you cannot find beef flat iron steaks for these tacos, flank steak will suffice. Keep in mind that flank steak can be tougher than flat-iron and may require a longer marinating and cooking time. You can also use hanger, skirt, or sirloin flap steak for this recipe.
- Spice: If you love spicy food, add an extra jalapeno or add habanero pepper sauce to the aji mixture. Experiment with the flavors and create something spectacular.
Leftover Flat Iron Steak:
- Store the sliced steak in an airtight container in the refrigerator for 3-4 days.
- Make it a breakfast item! Chop the meat into bite-sized pieces and make a delicious breakfast hash with your leftovers!
- You can also scramble the steak with eggs and make flat iron tacos breakfast style.
Try our Best Salmon Tacos!
- 2 pounds flat iron steak
- 12-14 corn tortillas
- 1 1/2 cups guacamole (lettuce, pico de gallo, queso, or cotija cheese)
- for marinade:
- 1 onion small, roughly chopped
- lime juice aim for two medium limes
- 2 jalapenos seeded and roughly chopped
- 1/4 cup cilantro
- 2 cloves garlic minced
- 1 tablespoon olive oil
- 2 teaspoons salt
- 1-2 teaspoons habanero pepper sauce (optional)
- 1 teaspoon black pepper
- Place all marinade ingredients into a food processor. Process until mixture is thick and smooth. Add more lime juice or oil if mixture remains chunky.
- Place flat iron steaks in a resealable plastic bag. Pour aji marinade over steaks and work it in making sure all surfaces of the meat are well coated. Seal bag and place into refrigerator for 6-24 hours.
- Preheat grill for medium-high heat.
- Remove steaks from bag and place onto grill. Cook 5-7 minutes per side or until steak reaches desired doneness. Place tortillas in a large piece of aluminum foil, wrap and place on the cooler part of the grill for about 5-7 minutes, turning once.
- Once cooked, remove steaks from grill and place onto a cutting board. Remove tortillas and set aside. Slice steaks into thin strips and serve in warmed tortillas with guacamole. If preferred, make a double batch of the aji sauce and reserve half to serve with the tacos.