Finely chop onions and garlic and put them in a sauté pan.
Sauté them over medium-high heat (10 out of 14 on my stove). They should not take color.
The pasta should be cooked in plenty of water according to the package instructions. Mine took 4 minutes.
Add the cream and turn up the heat slightly so it reduces a bit.
Take the pasta out of the pot and put it directly in the pan with cream and onions. The reason you shouldn't drain the water is that we want some of the cooking water to go with the pasta into the pan as it helps to combine the dish.
Turn the pan down to low heat (4 out of 14 on my stove),
When all the pasta is in the pan, add the mussels and mix everything well together.
Add a bit of lemon juice.
Stir a little and let it sit for 1 minute, so it combines, and the mussels get a bit of temperature.
Add freshly ground pepper and freshly grated Parmesan over the dish.
Chop parsley and season with salt. I had a bit of seaweed left over from our film shoot, so I used that instead of salt.
Bon appétit.