Over a medium heat soften the onion and carrot.
Add the sugar and vinegar and cook for two minutes.
Add the lentils and tomatoes and simmer for five minutes.
For the meatballs, place all the meatball ingredients into a food processor and blend until combined.
Transfer the meatball mixture onto a clean work surface and using your hands, shape into meatballs.
Cook the meatball in the oven at 180 deg C for 25 mins..
For the sauce
½ onion, chopped
1 carrot, chopped
1 tbsp brown sugar
1 tbsp balsamic vinegar
55g/2oz tinned lentils, drained
100g/3½oz tinned cherry tomatoes, drained
small handful fresh basil leaves, torn
For the meatballs
1 slice of bread, crusts removed
1 clove garlic, chopped
500g mince beef
1 free-range egg yolk
2 tsp olive oil