Season the salmon with salt and pepper. Pour on the sake and cover with plastic wrap. Microwave for 3 minutes. (Set aside, still covered in the plastic wrap).
Add salt and olive oil to boiling water and cook the penne. Cook it for about 2 minutes less than instructed on the package.
Wash the spinach and cut into bite-sized pieces. Place in a colander. For fuss-free prep work, use scissors to cut the spinach!
Once the penne has finished cooking, drain it through the colander on top of the spinach. (The hot water will cook the spinach to just the right degree.)
While the penne is cooking, slice the onion. Coat with salt, pepper, and flour. Sauté in olive oil in a frying pan.
Once the onion is slightly cooked, break the salmon into pieces and add it to the pan. Pour in the milk.
Once the milk starts to boil, add the penne and the spinach.
When the penne cooks to your desired degree of firmess, add the Parmesan cheese and stir it about 2 times. It's done!