We could only eat it on a special day which was once a month, so we always looked forward to theat day.

You don't need to use "only" in this sentence, but I think it conveys the meaning a bit better.

"the day" sounds a bit weird in this context. "that day" is talking about the "day" you just described and sounds more natural.

I also liked athe fried bread served on normal days.

I think that in English, to make a word more general (apply to more than just 1 thing/specific instance), you make the word into its plural version.

So in this case, "day" becomes "days", since you are talking about fried bread that is served on "ALL" normal days and not just "ONE" normal day.

It was seasoned with sweat soybean flour, and we always scrambled them in my classroom.

This sentence on it's own is completely grammatically correct, but it doesn't make sense to me. "scrambled" isn't a word that's used for bread (it's almost exclusively used for eggs), but I also don't know what you are trying to say with "scrambled" either.

We could eat it on a special day (which was) once a month, so we always looked forward to the day.

The "which was" is implied by the rest of the sentence, and while grammatically valid, I think it sounds better omitted.

I also liked athe fried bread served on normal day.

It was seasoned with sweat soybean flour, and we always scrambled for them in my classroom.

"scrambled them" would imply that you mixed it up as part of a dish (e.g. you might have "scrambled eggs" if you did that to eggs)

"scrambled for them" implies sort of chaotic running to get the bread.

We could eat it on a special day which was once a month, so we always looked forward to theat day.¶

"the" is fine grammatically, but it can be used for any day
"that" goes with "special" and "once a month" to highlight that day

I also liked a fried bread served on normal days.

We don't say "a bread." Maybe the reason we don't is that bread is usually cut into pieces, so we say "a piece of bread" or "a slice of bread."

It was seasoned with sweaet soybean flour, and we always scrambled to get them in my classroom.

Sweat forms on your skin you when you are very hot.
If scrambling refers to all the students rushing and pushing to get the fried bread, then you could say "scrambled to get them."
"Scrambled" can also mean mixed. "Scrambled eggs" are beaten, so the yellow and white are mixed before the eggs are cooked in a pan.

What wais your favorite type of school lunch?

My favorite type of school lunch wais sushi.

We could eat it on special day which was once in a month, so we always looked forward to ithe day.

I also liked a fried breads served on normal days.

It was seasoned with sweat soybean flour, and we always scrambled them in myour classroom.