1. What is referred to as shallots in America are called Eschallots in Australia. They look like tiny onions, but usually slightly longer. The flavour is stronger and sweeter than onions. You can substitute with brown or white onions - around ¼ cup finely minced onion (you need more because onion is not as strong).
2. You can substitute with light cream for a lighter option. But it isn't the same!
3. Parmigiano Reggiano is a type of parmesan and is only made in Italy. The flavour is deeper, nuttier and stronger and even a little bit sweet. It is more expensive than parmesan cheese. You can substitute with parmesan cheese, but I really think that if there is ever a time to splurge on Parmigiano Reggiano, it's on a dish like this!
4. It is key that the Parmigiano Reggiano is FRESHLY and FINELY grated. Otherwise it won't melt into the cream and you'll end up with grainy sauce. Store bought grated cheese is too grainy, even from good delis. Trust me, I've made that mistake before.
5. Hot smoked salmon comes in fillets in vacuum sealed packets in the refrigerator section of supermarkets. It is already cooked.
However, you can make this with normal cooked salmon too. To do this, just sprinkle the salmon with salt and pepper, heat a little oil in a skillet over medium heat and cook the salmon for around 8 minutes, or until just cooked through. Then flake and use per the recipe.
6. However long the pasta packet suggests as the cooking time, subtract 1 minute for al dente because the pasta will continue cooking with the sauce. My fettuccine packet says 12 minutes so I boil it for 11 minutes.
7. You need a deep fry pan to cook pasta because the pasta is tossed with the sauce to emulsify (magic that happens with starch in pasta is cooked a bit with the oil in the sauce) which makes the pasta extra glossy, thick and rich. This is a key Italian tip for making amazing pastas!
If you don't have a large deep fry pan, use a very large pot.
8. The sauce should be silky smooth and a thin film should cling to each strand. The pasta should not be drowning in sauce. If the sauce goes gluey because you overcooked it or the heat is too high, just add a touch more of the pasta water (i.e. the extra mug of water you reserved) and it will go back to silky smooth.