Add the rapeseed oil to a frying pan and place it over medium heat.
Add the onions to the pan and sauté for 1-2 minutes.
Mix 1 teaspoon of sugar into the onions and sauté for another 3-4 minutes, until translucent.
Add the garlic and ginger to the pan and fry for 1-2 minutes until fragrant.
Add the ground lamb to the pan to brown for 4-5 minutes.
Mix in 1 teaspoon of ground cumin, the coriander, turmeric, and chili powder.
Add the lamb stock, tomato puree, and salt and pepper to the pan.
Stir everything well and then leave the mixture to simmer for 15 minutes. When the time is up, remove the lamb mixture from the heat.
Meanwhile, add the yogurt, mint, 2 tablespoons chopped cilantro, lemon juice, a pinch of cumin, and a pinch of sugar to a bowl, stirring to create the mint sauce.
Slice the pita breads in half.
To serve, fill the pita breads with a spoonful of mango chutney, a spoonful of the mint sauce, the lamb mixture, some fresh diced tomatoes, and some more cilantro.