Verified answer

In earlier times, "ず" expressed negative, and "ぬ" was the attribute form of "ず."

And "む" expressed "will," and came to be pronounced as "ん."

They began to mistake this "ん" n with "ぬ" nu.

In time, "ん" came to express negative.

"しりません" means "do not know."

"To know" is "しっている," and "しっています" is the polite form.

"Not to know" is "しらない" "しりません."

"しらない" is the negative form of "しる" and "しりません" is the negative form of "しります."

Strangely, "しっていない" "しっていません" sound awkward.

And to express "to know," "しる" and "しります" aren't used.

Possitive "しっている" "しっています," and negative "しらない" "しりません."

You can also say "りょうりのつくりかたがわかりません."

しる is the short form of "to know." So しりませんis the long negative form of "to know."

So it means you dont know. But instead of saying つくりかた which i think your saying it this way 作り方 (way of making) it might be easier to say りょうりするのがしっていません。しっていません means I do not know.