Using Eiruv Tavshilin to Cook for a Gentile Shabbos Guest

Question

When cooking on Yomtov for Shabbos (allowed with the eiruv tavshilin) may one also cook for a gentile guest that he will be having at the Shabbos meal?

Even though one cannot cook on Yomtov for a gentile, if the halacha is according to the opinion that the needs of Shabbos are permitted to be done on Yomtov, but the Chachomim required an eiruv tavshilin to do so, should the gentile guest be considered included in the category of "needs of Shabbos" by using the heter of ribui bishiurim or not?

And if the reason for being able to cook on Yomtov for Shabbos is in accordance with the opinion that we say since you may get guests on Yomtov and it is permissible to cook for them to eat on Yomtov, you may cook for Shabbos based on that possibility that the food may be needed for Yomtov, and the Chachomim required an eiruv tavshilin for this, do we say that this reasoning only applies to cooking for Jews, since it is only permissible to cook for Jews on Yomtov, or could we say that this reasoning, combined with using the heter of ribui bishiurim allows any act of cooking, no matter that you intend for some of it to be for your gentile Shabbos guest?

For clarity's sake, let me add what I already wrote as a comment:

My question is about actually increasing quantity on yomtov for a gentile who will be eating at your house that shabbos, based on eruv tavshilin. Increasing quantity is allowed on Yomtov for one day to the next as long as not specifically stated since it involves the same action as the one you would have done had you not increased the quantity. Could one do so for the sake of his gentile Shabbos guest?

Answer 1

Rav Asher Weiss was asked this She'ailah last week and answered that as far as inviting the gentile for Shabbos, there is no problem. But you may not be marbeh bishiurim (increase specific quantities) on Yom Tov for him to eat on Shabbos.

Answer 2

The Pasuk says “Ach Asher Yai’achail L’chol Nefesh Hu L’vado Yai’aseh Lachem”, Beis Hillel learns that Meleches Ochel Nefesh is permitted on Yom Tov only for “Lachem” – only for Bnei Yisrael. One may not perform these Melachos for non Jews or for animals (even if owned by Jews). (Baitzah 20b) Because one may not cook on Yom Tov for non Jews, Chazal prohibited inviting non Jews to a Yom Tov meal. As the host of an invited guest, a person may feel obligated to provide plenty of food, and therefore, may come to cook for the non Jew. (Baitzah 21b; Shulchan Aruch O.C. 512:1) This applies even in a situation where the Jewish host prepares all the cooked food before Yom Tov. Even then, there is a concern that he might add a dish or boil water for the gentile guest. (Mishna Brurah 512:3).

Based on the above you would not be allowed to cook for a non Jew on Yom Tov for any reason.

There are a number of exceptions to this rule. Firstly, if Yom Tov is on Shabbos when cooking is totally prohibited, there is no prohibition to invite a non Jew. Secondly, if an uninvited non Jew shows up, one may serve him food that has already been cooked. We are not concerned that the host will feel obligated to cook anything extra. Thirdly, one may serve food to a non Jewish servant, due to similar reasoning. (Shulchan Aruch 512:1)

(Insights to the Daf - Yoma 28b) The Gevuras Ari mentions that according to the opinion of Rabbah in Pesachim 46b an Eruv Tavshilin only allows you to cook for Shabbos on Yom Tov due to the principal of Ho'il. When one cooks for Shabbos on Yom Tov he is actually cooking for Yom Tov itself, since it is possible that guests will visit him on Yom Tov and he will need to serve them this extra food. However the application of Ho'il only allows him to cook for Jewish guests.