Rashi says she baked cakes not bread because she was in Niddah. How does this make any sense? We bake bread whenever.
There is a mistake in your lecture of Rashi, the "cakes" are bread, ugot refers to the shape form. Later rashi writes that they eat butter, milk and meat but the bread (& / the cakes) is not mentioned. Why? Because she became Nidda, and the dough became unclean. They were stringent to eat "Chulin Betahara" according to Rashi. This is not a strict obligation from Halachic point of view. Nowadays, we have problem with dead uncleaness, or Tum'at Erets Haamim, we cannot be clean.
About the "Make cakes".
1. The verse:
the word is Ugot.
2. The translation of Onkelos:
the aramic translation is "Gritzin".
3. We found Gritzin in Mishna (Betsa 2, 6):
וְאֵין זוֹקְפִין אֶת הַמְּנוֹרָה בְיוֹם טוֹב, וְאֵין אוֹפִין פִּתִּין גְּרִיצִין אֶלָּא רְקִיקִין. אָמַר רַבָּן גַּמְלִיאֵל, מִימֵיהֶן שֶׁל בֵּית אַבָּא לֹא הָיוּ אוֹפִין פִּתִּין גְּרִיצִין, אֶלָּא רְקִיקִין.
According to Rabban Gamliel, to bake a great quantity of dough is prohibited on Yom Tov because of the great effort needed. This great quantity (גריצין gritzin) of dough (Pat, pitin). Rashi says that Pitin Gritzin are thick loaf of bread, Tosfot Betsa 22b says large loaf of bread.
So the translation "Ugot" ="gritzin" = "cake" may be a consequence of the expression Ugot nowadays in modern Hebrew and doesn't come from the traditional lecture of the verse.
Very interesting discussion of language usage. One confusing point to me. The term "pat" actually means "piece". In Tanac"h, we see the term "pat lechem" frequently. I don't think that the term "pat" is used to mean "dough", at least not in Tanac"h. Has the Talmud changed the meaning of this term? I think even in the Talmud, it is used to refer to bread, but even there, I still thin it means "piece" (of bread). Nov 16, 2016 at 16:39
@DanF You are sure that pat means piece. I believed that it is dough only. I think that in loazim also as pasta in Italian, pâte in French. It is also a symbolic word for subsistence, in French pitance. Piece is kikar I think. What do you think?– koutyNov 16, 2016 at 17:11
I'll find a M.Y. question that discussed the meaning of "pat". I know it's around as I answered it a few months ago. "Kikar" means "loaf". Nov 16, 2016 at 19:02
@DanF Yes loaf, it was my intent. I understand that piece is slice...– koutyNov 16, 2016 at 19:22
I found the M.Y. answer about the definition of "pat" judaism.stackexchange.com/a/70431/5275 Nov 16, 2016 at 19:59