Put a large pan of salted water on to boil. Put the yogurt in a large dish. Measure out 2 tsp of the garam masala and stir it into the yogurt with a pinch of salt and pepper.
Pop the chicken breasts between 2 sheets of cling film. Bash the chicken with a rolling pin or pestle till they’re around 1 cm thick. Add them to the yogurt marinade. Turn to coat thoroughly. Set aside..
Scrub and chop the potatoes into small chunks. When the water in the pan is boiling, add the potatoes. Simmer for 15-20 mins till tender, but not too soft, when pressed with a fork. Drain well.
While the potatoes simmer, slice both the fat cheeks off the mango, as close to the stone as possible. Slice off the thinner cheeks. Slice off the skin. Cut the flesh into sticks. Pop in a bowl.
Shred half the lettuce Add it to the mango. Halve the cucumber (use half in salads and sandwiches along with your leftover lettuce). Take one half and slice it lengthways . Run a teaspoon down the middle to scoop out the seeds. Roughly chop the cucumber. Add to the lettuce and mango. Finely slice the chilli. Flick out the seeds for less heat, if you prefer. Add the chilli to the veg. Add ½ tbsp olive oil to the bowl. Season with salt and pepper. Toss to mix.
Warm 1 tbsp olive oil in a griddle or frying pan. Add the drained potatoes. Fry over medium heat for about 5 mins till the potatoes are a little golden. Add them to the bowl of veg. Warm another ½ tbsp oil in the pan.
Add the chicken breasts to the pan, shaking off any of the excess marinade. Fry over a medium-high heat for 5-6 mins till dark golden. Flip and fry for another 5-6 mins till the chicken is browned and cooked through – the juices should run clear. Slice and serve with the salad and lemon wedges for squeezing.