Preheat the oven to 200C, fan-forced. Thinly slice the onion. Trim the lettuce, then separate the leaves. Halve the tomato and thinly slice. Combine 2 tsp olive oil and 1 tsp balsamic vinegar in a large bowl and season with salt and pepper.
Step 2 — Caramelise onion
Heat 2 tsp olive oil in a small frypan over medium-high heat. Cook the onion, stirring regularly, for 6 mins or until soft and golden. Add ½ tsp sugar and ½ tsp balsamic vinegar and cook, stirring, for 2 mins or until the onion is caramelised. Remove the pan from the heat.
Step 3 — Pan-fry steaks
Combine the mint and garlic seasoning and 2 tsp olive oil in a large bowl and season with salt and pepper. Add the steaks and turn to coat. Heat a medium frypan over high heat until hot (see Kitchen 101). Reduce the heat to medium-high and cook the steaks, turning regularly, for 4-6 mins for medium-rare, or until cooked to your liking. Remove from the pan and rest for 4 mins.
Step 4 — Bake rolls
While the steaks are resting, cut the bread rolls in half. Put on an oven tray, cut-side up, and bake for 4-5 mins until lightly toasted.
Step 5 — Serve up
Slice the steaks. Spread the rolls with the aioli. Layer the bases with some lettuce and tomato, then add the steak strips and onion. Sandwich with the tops. Add the remaining lettuce and tomato to the dressing and toss to combine. Divide the steak sambos and salad among plates and enjoy!
Step 6 — Kitchen 101
It's important to have your pan very hot before adding the beef, otherwise it may stew slightly and become tough. To ensure tender beef, slice the steak against the grain.