Peel and chop the onion

Add to a pan with some oil and fry gently till soft.

Add the stock and boil for a couple of minutes to reduce.

Add the maple syrup, mustard, whisky and lemon juice and bring back to the boil.

Core the apples and cut into slices.

Add the apples to the sauce and cook gently until the apples soften, but are not mushy.

Serve the apples with a sprinkle of the sauce. If preferred the onions can be served as well but I just served the apples.