Chimichurri is a sauce typically made from parsley, garlic, oil, vinegar and salt. It is used to flavour flank steak and can be a delicious condiment for any meat or vegetable dish. It's easy to make and can be stored in the fridge for up to 3 days.
In a small bowl, whisk together chimichurri sauce and olive oil.
Season flank steak with salt and black pepper, then spread chimichurri mixture all over the steak. Place steak in a baking dish or on a plate and let it marinate for at least 30 minutes or up to 2 hours.
Preheat oven to 400 degrees F.
On a baking sheet, toss red onion, red bell pepper, and jalapeño pepper with olive oil.
Spread mixture on top of the steak and bake for 25 minutes, or until steak is cooked through.
Let rest for 10 minutes before slicing into thin strips.