1) why does it say in L’T melachot (rav ribiat) that relish can be made even if it produces a thicker mixture? you cannot ever produce a thicker mixture correct?
2) it also mentions that it is best to make a thick mixture before shabbot such as liver with hard boiled eggs and oil which makes a blilah avah – but then it says later that this can be done with 2 shinuiim? can you or cant you? also it says that with blilah racha contrast to avah since its only derabanan you can do this with the 2 shinuiim ; why is this special if this can apparently also be done wth blilah avah?
1. I don’t have the book. In general, it is forbidden to make a thick mixture in the normal manner. However, this is only true when a solid and a liquid are being mixed together, so that the small pieces of the solid fuse together to form the mixture. I don’t know what case Rav Ribiat is referring to.
2. Authorities dispute whether it is permitted to rely on doing two shinuyim for belilah avah (a thick mixture, such as a dough). This depends on the interpretation of the Rema (321:16), with Magen Avraham prohibiting, but Taz permitting. The Mishnah Berurah rules stringently, and therefore one should prepare the mixture before Shabbos. However, if the mixture can’t be prepared before Shabbos, there is room for leninency, ensuring that the two shinuying are made. For a belilah racah, it is permitted to make the mixture with two shinuyim.
The laws of Lash are quite complex, and it is recommended to spend some time studying the Shulchan Aruch and the Mishnah Berurah, before moving on to the “summaries” sefarim.