Hi Yu Tata, This is probably taken from a restaurant advertising its dinner which is special because you have a say in customising the food that is served to you. "Selection of platters" means you can order different platters (which is a large flat plate containing a variety of smaller dishes or different foods. Examples: Seafood platter (consisting of prawns, shrimps, fish and so on) or fruit platter (consisting of sliced apples, watermelon, papaya and so on). Besides that, you can also choose your favourite dessert from the menu. ("of choice" means your favourite choice. Example: Sauvignon blanc is his drink of choice (his favourite drink). The word "selection" is used for the platters to express the idea that there are many types to choose from (meaning that you are "spoilt for choice".) "of choice" expresses the idea of something that is catered specifically for you. Just as a side discussion, you may come across advertisements that use the phrase "dinner special" instead. It is also commonly used. I hope this helps.

special dinner - this is odd - it would normally be 'dinner special' = 定食。

The word “special” is being used to indicate that this is not a “normal” dinner, i.e. a single plate per person. Instead, this dinner is a "selection of platters”, which is a dinner where people have to take what they want from large shared plates (similar to a buffet, but smaller).