Bring a large skillet filled with about 3 inches of water to a boil. (alternatively, you can do this step before you boil the pasta and use the same water) Add the sausage links and boil for 5 minutes until about halfway cooked through.
Remove the water from the skillet and preheat the same skillet to medium heat with the olive oil. Slice the par-cooked sausage links on a diagonal into 4-5 pieces each.
Add the sliced sausage to the olive oil and crisp for about 3 minutes on each side until golden brown. Remove the seared sausage from the skillet.
To the same skillet, add the onion and peppers to the sausage drippings with a sprinkle of salt. Stir to cook the veggies until they are soft and lightly brown at the edges. Add the garlic and stir into the peppers and onion for one minute.
Add the canned tomatoes with another sprinkle of salt and a splash of the pasta cooking water. Stir to combine and reduce the heat to low. Let the sauce simmer for 10 minutes, tasting as you go for seasoning - the sauce should be very flavorful.
When the sauce has simmered, add the pasta, sausage, sour cream, and parmesan to the skillet. Stir everything together, taste once more for seasoning, and serve! If the pasta seems dry, splash in a little more cooking water until you achieve a consistency that you like.
Top with more parmesan and any fresh herbs you like right before serving. Enjoy!