Preheat the oven to 220C, fan-forced. Line an oven tray with baking paper. Cut the unpeeled sweet potatoes into 2cm chunks. Put on the lined tray, drizzle with 2 tsp olive oil and bake on the upper oven shelf for 20 mins or until tender.
Step 2 — Cook bacon
Meanwhile, heat 1 tsp olive oil in a large frypan over medium-high heat. Cook the bacon, stirring, for 5 mins or until lightly browned. Remove the pan from the heat.
Step 3 — Make patties
Put the beef mince, three-quarters of the bacon, half the barbecue seasoning and 2 tsp barbecue sauce in a large bowl. Using damp hands, combine well, then shape into 2 equal patties, slightly larger than the base of a roll. Put the remaining bacon in a separate bowl and reserve the pan. Cut the bread rolls in half.
Step 4 — Cook patties
Heat 1 tsp olive oil in the reserved pan over medium-high heat. Cook the beef patties for 3 mins each side or until cooked through. Remove from the pan and cover to keep warm. Return the pan to medium-high heat. Cook the rolls, cut-side down, for 1-2 mins until toasted. Transfer the rolls to an oven tray and bake on the lower shelf for 4 mins or until warmed through.
Step 5 — Make bacon mayo
While the rolls are baking, add the remaining barbecue seasoning and 2 tbs mayonnaise to the remaining bacon and stir to combine. Combine 1 tsp olive oil and ½ tsp red wine vinegar in a large bowl and season with salt and pepper. Add the salad leaves and toss to coat.
Step 6 — Serve up
Thinly slice the tomato. Spread the roll bases and tops with the bacon mayo. Layer the bases with the tomato, beef patties and salad leaves, then sandwich with the tops. Serve with the sweet potato gems and any remaining salad leaves. Enjoy!