Cook pasta according to instructions and set aside.
In a seasoned cast iron pan on medium heat, sear the shrimp with salt/pepper and some oil until they turn pink. Set aside.
In the same pan, saute the sliced onions until they start to turn golden. Add the minced garlic and saute for another 2 minutes.
At this point, add the roasted red peppers, Italian herbs, red pepper flakes, and chicken stock. Turn down the heat to low and simmer for a few minutes.
Then add the spinach, heavy cream, and the sauteed shrimp. Simmer for 5 more minutes, stirring constantly, until the spinach has wilted.
Finally, stir in the cooked pasta, top with Parmesan cheese, and serve warm.
Notes
Note that the traditional version uses sun-dried tomatoes rather than roasted red peppers (but we used what we had in the pantry!).