I'll just get it out of the way. The type of "Singapore noodles" known outside of Singapore does not actually exist in Singapore. When I moved to Singapore, I didn't know that. As I walked along the hawker stalls, I kept looking for the only dish of Singapore that I'd heard about, hoping to taste a terrific authentic version. Slowly I began to figure out that what I knew as Singapore noodles was in fact a noodle known here as bee hoon (thin rice vermicelli) in a simple stir-fry dish of mild soy sauce seasoning, vegetables, and a modest sampling of seafood such as shrimp (known as prawns here) and squid (sotong).
A filling plate of bee hoon will only set you back about $3 to $6 SG (about $4 US). Also, just about everywhere is a bare bones version known as "economical bee hoon." Economical bee hoon is the way to go if you're trying to fill your belly at bargain. You can grab a plate of it for only $1 SG (or about 80¢ US).
The main difference between Westernized versions of Singapore noodles and the real thing is that there isn't any curry powder in a Singapore bee hoon dish. The noodles are also served up pretty mild in flavor—not spicy at all. With all of the other fiery dishes around, I find this an especially refreshing noodle dish. Plus, there are always hot chilies available on the side if you want to heat things up.
Even after doing some research, I haven't been able to suss out how curry powder got added to the mix in Westernized Singapore noodles. My guess is that it was a way to merge the flavors of two strong Singaporean ethnicities, Chinese and Indian, into a quick fried hawker-style dish.
Fried vermicelli is a very homey dish, with families cooking it up at home according to the flavors that appeal to their own personal tastes and what they happen to have on hand. With this in mind, I've fried up my own version for you to try at home. A gas stove and a wok works best to try to achieve as much wok hei (a unique flavor that comes from a wok and high flame) as possible. Though even with that, my dish could not seem to fully replicate that which came from the well seasoned and jet-fired woks at my local hawker stand.
Fried bee hoon is easy and fast. No parcooking of the noodles is necessary. Just soak, drain, and fry. To fry the noodles right, and to keep the noodles from sticking to the pan, don't be too stingy with the cooking oil. You can buy pickled chilies in the store, but making them yourself is a breeze.