Preheat the oven to 220C, fan-forced. Line 2 oven trays with baking paper. Cut the unpeeled sweet potato into 2cm-thick fries. Put on a lined tray, drizzle with 1 tbs olive oil, season with salt and pepper and toss to coat. Roast for 20 mins or until golden and tender.
Step 2 — Prep ingredients
Meanwhile, crush or finely chop the garlic. Thinly slice the tomato. Peel the cucumber into ribbons with a vegetable peeler. Coarsely grate the cheese. Put the garlic, beef mince, 2 tsp barbecue seasoning and 2 tsp barbecue sauce in a large bowl and season with salt and pepper. Using damp hands, combine well, then shape into 2 equal portions.
Step 3 — Cook beef patties
Heat 2 tsp olive oil in a medium frypan over medium-high heat. Add the beef portions and press down on each with a spatula to flatten into a patty slightly larger than the base of a bread roll (see Kitchen 101). Cook for 3 mins each side or until browned and cooked through. Remove from the pan.
Step 4 — Warm bread rolls
While the patties are cooking, cut the bread rolls in half. Put on the remaining lined tray, cut-side up, and scatter the cheese over the roll tops. Bake for 5-6 mins until warmed through and the cheese is melted. Combine 2 tbs mayonnaise and the remaining barbecue seasoning in a bowl.
Step 5 — Serve up
Spread the roll bases with the mayo mixture, then layer with the tomato, beef patties and cucumber. Sandwich with the cheesy tops. Serve with the sweet potato fries and enjoy!
Step 6 — Kitchen 101
As their name suggests, 'smash' burgers are formed by flattening the beef in the pan rather than forming it into burgers before cooking. The rough uneven texture allows the edges to crisp up. Make sure your pan is hot before adding the beef so they brown up nicely.