Learn Russian: Они сделали подделку так же быстро, как оригинал. - They made the fake exactly as fast as the original.

We use так же because it modifies the adverb быстро (fast). If we were describing a noun with an adjective (like "The fake is as fast as the original"), we would use такой же быстрый, как. But here, we are comparing the action of how they made it, so we need the adverb form.

Why is так же written as two words here? I've seen также written as one word.

When you are making a comparison meaning "just as... as", it is always written as two separate words: так же ... как. The single word также means "also" or "too" and is not used for comparisons.

How does the word подделку mean "fake"?

Подделку is the accusative form of the noun подделка. You can spot the familiar root from делать (to do or make). The prefix под- (under) often adds a sense of something being done secretly, sneakily, or falsely. So a подделка is something "made falsely" — a fake or forgery.

What case is оригинал at the end of the sentence?

It is in the accusative case, just like подделку. The full implied thought is "as fast as they made the original" (как они сделали оригинал). Because оригинал is an inanimate masculine noun, its accusative form looks exactly the same as its nominative dictionary form.