The most important ingredient to fried spaghetti (besides thinly grated gouda) is Ubena Spaghetti-Gewürzmischung.
As every member of my generation that got childhood exposure to this rare spice can testify: it's the best stuff ever, or at least the most significant contribution that the city of Bremen made to the world. Unfortunately, the Ubena factories fell prey to Unilever in 2000, and were dismantled by a competitor (Fuchs) later that year. Fuchs had their own Spaghetti spice, a far inferior concoction, and in an act of vileness and hubris, Ubena Spaghettigewürz has been discontinued.
As a result, millions (or at least dozens) of fellow German spaghetti eaters have suffered from grave and unabating withdrawal for more than a decade. Not any more! Thankfully, a group of mad hobbyist food scientists got to work and came up with a passable re-creation of our childhood drug.
Here is what you need for 100g:
Paprika (dried red peppers, hot): 36g
Onion (dried and granulated): 22g
Tomato powder: 21g
Lovage root: 4g
Mono Sodium Glutamate (I know, I know): 6g
The most important part seems to be the lovage (Liebstöckel) root. Lovage seems to be rarely used outside of middle Europe, and then it's usually leaves and not roots, but here, we cannot do without. I am off to fry some Spaghetti now.