Preheat the oven to 220C, fan-forced. Thinly slice the spring onion. Shred the carrot using a julienne peeler or coarsely grate with a box grater. Combine 1 tbs white vinegar and 2 tsp sugar in a large bowl. Add the spring onion and carrot and toss to combine. Set aside to pickle, tossing occasionally, until needed.
Step 2 — Make patties
Put the beef mince and South American seasoning (see Make it yours) in a large bowl and season with salt and pepper. Using damp hands, combine well, then shape into 2 equal patties, slightly larger than the base of a roll.
Step 3 — Cook patties
Heat 1 tsp olive oil in a medium frypan over medium-high heat. Cook the beef patties for 3 mins each side or until browned and cooked through. Remove the pan from the heat.
Step 4 — Toast rolls
Meanwhile, cut the bread rolls in half. Put on an oven tray, cut-side up, and bake for 5-6 mins until lightly toasted.
Step 5 — Serve up
Drain the pickled veggies and return to the bowl. Add the salad leaves, season with salt and pepper and toss to combine. Spread the roll bases and tops with the mayonnaise. Layer the bases with the salad and beef patties, then sandwich with the tops. Serve the remaining salad on the side and enjoy!
Step 6 — Make it yours
If you like a kick of heat, add a pinch of chilli flakes to the beef mince in Step 2, or scatter over to serve if it's just for you.