Peel and wash the carrot. Clean and wash spring onion and bell pepper. Cut vegetables into fine strips. Heat 1 tablespoon of oil in a pan. Fry the vegetables for about 4 minutes at medium heat.
Dust with curry and season with salt and pepper. Leave to cool. Wash the coriander and dab dry. Pluck the leaves and chop them coarsely. Mix turkey mince, vegetables, breadcrumbs and coriander. Form 4 flat meatballs.
Heat 2 tablespoons of oil in a frying pan and fry the turkey meatballs for about 4 minutes on each side. Wash the salads and pat dry. Wash tomatoes, dab dry and cut into slices. Cover the meatballs with cheese and put them on a baking tray.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 5 minutes. Halve the avocado and remove the core. Peel halves and cut into slices. Sprinkle with lemon juice.
Cut the hamburger buns in half. Spread the bottom half with ketchup and mayonnaise. Cover with tomatoes, lettuce, turkey meatballs and avocado and finish with the upper half of the roll. Serve the turkey burger with cherry tomatoes and celery as desired.