Can anyone share a recipe please that is sure to impress my in-laws?

It depends on what your MIL likes. - if she prefer traditional chinese cookings, you can try to cook braised chicken, salty egg prawns and etc. - if she has sweet tooth, you can bake some cakes like mango cheesecake/chiffon for her. - if she likes desserts, there are a lot of nice dessert recipes, e.g. mango sago dessert, green bean soup and etc. I always like to refer to this blogger, http://nasilemakloverindex.blogspot.sg/ for ideas. She has an index pages for you to find different types of dishes in her main page.