Preheat the oven to 200C, fan-forced. Line 2 large oven trays with baking paper. Cut the unpeeled sweet potatoes and carrot into 1.5cm-thick wedges. Thickly slice the onions.
Step 2 — Roast vegetables
Put the wedges and onion on the lined trays, keeping them separate. Drizzle with 1 tbs olive oil and 2 tsp honey, season with salt and pepper and toss to coat. Roast, swapping the trays halfway, for 30 mins or until golden and tender.
Step 3 — Make patties
Meanwhile, put the beef mince and barbecue seasoning in a large bowl and season with salt and pepper. Using damp hands, combine well, then shape into 4 equal patties, slightly larger than the base of a bun.
Step 4 — Cook patties
Preheat the grill to high. Heat 1 tbs olive oil in a large frypan over medium-high heat. Cook the beef patties for 3 mins each side or until cooked through. Halve the bread rolls. Put the rolls on a large oven tray (see Cooking tip), cut-side up, and grill for 1-2 mins until lightly toasted.
Step 5 — Assemble and serve up
Spread the bread roll bases with 80ml (⅓ cup) mayonnaise. Layer with the beef patties, onion and some salad leaves. Sandwich with the roll tops. Drizzle 1 tsp red wine vinegar over the remaining salad leaves. Serve the burgers with the wedges and salad. Enjoy!
Step 6 — Make it yours
Use up veggies in your fridge to add to your salad, such as sliced tomato, cucumber or capsicum.