A forum-friend provided this recipe, when I asked for suggestions for a spare chicken breast (other one went into curry.) Very yummy indeed, thanks!

Season chicken breast with salt, pepper and your favourite spice blend.

Bake or grill it. (About 30-45 minutes at 175-200 degrees C)

Once cooked let it rest and start to cool, whilst you prepare the bits to go with it.

Smear mayonnaise and mustard on two slices of bread. Slice the chicken thinly into strips. Then add lettuce leaves to the bread, the sliced up warm chicken, and top with tomato slices.

I mixed the order, adding the chicken and then the lettuce, but it still tasted nice:

Sorry about the rubbish photo. Taken on my phone.