Heat a pot of water for the spaghetti and season lightly with salt.
In a saucepan, heat the spinach until almost dry - you can tell it's almost dry when the spinach starts to stick at the bottom of the pan. Remove the spinach and wash the saucepan.
Dry the saucepan and heat over medium heat. Add in 2 tablespoons of oil. Season the sliced chicken fillets with salt and freshly ground black pepper. Sear the chicken until browned and cooked. Remove and set aside. (Skip this step if you are not using any chicken.)
By now your pot of water should be boiling, add in your spaghetti.
Test your spaghetti - once it's al dente, drain and add into the cream sauce. Toss and coat the pasta, adding more cream if you want it more creamy or a little pasta water to loosen the sauce. Plate the pasta, drizzle with some extra virgin olive oil and serve immediately.
NOTES
- Instead of spaghetti, use linguine or fettuccine as they mop up the sauce better. - Use whatever fresh and flavourful mushrooms you can find - I used bunashimeji, but portobello will be more flavourful and meaty.