- Place the breadcrumbs in the bowl of a food processor with the onion, carrot, apple, minced beef, garlic, thyme and Parmesan and blitz until finely chopped.
- Transfer the burger mixture to a bowl and use your hands to shape it into 20 mini burgers.
- Preheat the grill to high.
- Line a baking sheet with foil and lightly grease the foil.
- Place the burgers on the baking sheet and place under the grill for 5 minutes. Turn over and grill for a further 3–5 minutes until lightly golden and cooked through.
- Serve in mini burger rolls, if you wish, with carrot sticks, cherry tomatoes and ketchup.