Step 1

In a large shallow dish, whisk together the olive oil, Worcestershire, lime juice, garlic, cumin, chili/pepper flakes, salt and sugar until combined. Pour half of the marinade over the beef fillets, turning them to coat evenly. Add the capsicums/peppers with the onion to the remaining marinade and coat evenly. Cook immediately OR marinade for 1-2 hours in the refrigerator (or over night) for a deeper flavour.

Step 2

Heat a pan (cast iron) or heavy skillet over medium-high heat and drizzle in 2 teaspoons oil. Add the capsicums/peppers and onion and fry for a few minutes, until they're cooked but still crunchy and vibrant in colour and have nice chargrilled marks on them. Remove to a warm plate and set aside.

Step 3

In the same pan over high heat, add a little extra oil (to prevent sticking), and fry the meat in batches until cooked to your liking. Remove and allow to rest on a cutting board for 5 minutes, and then slice thinly.

Step 4

Preheat grill/sandwich press, and prepare sandwiches with the capsicums/peppers and onions, steak slices, Greek yoghurt/sour cream, avocado slices, cheese and coriander/cilantro leaves. Place them into the grill/press and cook until warm and cheese has melted through.

Step 5

Serve with limes, extra Greek yogurt/sour cream and salsa!