Slice the steak and peppers into thin strips. Cut the chilli into thin rings.
Put the steak, chilli and pepper slices in a bowl, mix with the spices and season with salt & pepper.
Peel the mango, slice into thin strips. Set aside.
Rinse the lettuce leaves, wipe clean with paper towels and put them into a serving dish.
Heat a spoonful of olive oil in a frying pan, add the marinated steak and pepper and cook on medium heat for 5-10 minutes.
Leave to cool slightly, then transfer them onto the lettuce leaves. Scatter the mango pieces around.
Mix the yogurt with the lime juice and and thyme leaves.
Serve it warm with the yoghurt mixture on the side.