Can a housekeeper prepare Shabbat food?

ב"ה Shalom In order to properly answer your question, a lot more details are necessary. Firstly, I assume that your housekeeper is not Jewish, therefore you are asking. Secondly, there are two dimensions to your question. There is the issue of "bishul goyim", that is certain foods (which are Kosher) which are cooked by a non-Jew, which otherwise would be inedible without cooking, are forbidden, after being cooked by the non-Jew. The idea behind is to limit socialization which might lead to intermarriage between Jews and gentiles. The other issue is that a non- Jew may not do work for you which is forbidden on Shabbat, if not under specific circumstances, which I will not got into now. The housekeeper may prepare food for Shabbat before Shabbat which does not involve cooking of foods as aforementioned because of the issue of food cooked by a non-Jew. The housekeeper may prepare food on Shabbat itself which does not involve actions which constitute a desecration of Shabbat. You may ask your question again and be more specific, this way I will be answer you more accurately. All the best