Steak: Bring the steaks out and let them sit at room temperature for anywhere up to 1 hour before cooking. Season with 1 tsp salt and 1 tsp pepper and set aside.
Vegetables: Finely shred cabbage and 1 avocado. Finely dice 1 small red onion and 1 large handful of coriander. Add onion and coriander to a bowl and add 50g softened butter. Add 1 tsp red wine vinegar and 1/2 tsp salt to the butter, along with 1 tsp crushed garlic. Mix well and taste, adjusting seasoning if required.
Cook steak: Heat a large pan to high heat and add 2 tsp canola oil. Once the pan is hot, cook steaks for 2-3 minutes per side until cooked to your desired level. Remove, rest for 2 minutes then slice.
Serve: Lightly toast your bread, and spread 1 tbs aioli on each piece, then add avocado and cabbage. Top with sliced steak and serve with a spread of chimichurri butter.