Step 1 Place mince, zucchini, half the carrot, coriander, breadcrumbs and egg into a large bowl and season with pepper. Using clean hands, mix until well combined. Form into 4 patties. Place patties on a foil-lined baking tray, cover and chill in the refrigerator for at least 10 minutes.
Step 2 Meanwhile, cook sweet potato chips according to packet instructions. Spray a chargrill pan or frying pan with oil and place over medium-high heat. Grill patties for 4–5 minutes each side, or until cooked through.
Step 3 Meanwhile, place remaining carrot, cabbage and tzatziki into a bowl. Mix well.
Step 4 Spread 1–2 tablespoons cabbage mixture over the base of each roll, then top with a patty, rocket and bun top. Serve with sweet potato fries.