In Gensis 18 -6, when Avrohom hosted the angels, he told his wife to
מַֽהֲרִ֞י שְׁל֤שׁ סְאִים֙ קֶ֣מַח סֹ֔לֶת ל֖וּשִׁי וַֽעֲשִׂ֥י עֻגֽוֹת:
"Hasten three seah of meal [and] fine flour; knead and make cakes."
Rashi explains that the inferior 'meal' wasn't for their consumption but rather to make a starchy covering for the cooking pot.
קמח סלת: סלת לעוגות, קמח לעמלן של טבחים, לכסות את הקדרה, ולשאוב את הזוהמא:
The problem is that this starch like form is not allowed to be owned on פסח and is explicitly listed in the first משנה of אלו עוברים. https://hebrewbooks.org/shas.aspx?mesechta=4&daf=42&format=pdf.
It is a well documented question when this event took place, but most hold that it was on פסח. There are opinions saying it was sukkos (even bringing support from another Rashi), but how do the פסח camp square this question?
I wonder if it is possible to make a starchy dough by using liquid that doesn't cuase leavaning?