Add olive oil to a large pot set over medium heat. Add chopped onions and cook for about five minutes, until onions are soft. Add minced garlic and the ground sausage (removed from casings). Cook for 5-10 minutes, breaking up sausage with a spoon, until sausage is cooked through.
Add sliced mushrooms and sautee for a few more minutes. Then add chicken broth (I use Better than Bouillon), pasta and 1-2 tablespoons of Sriracha. If you like things mild, definitely start with 1 tablespoon.
Cover pot with the lid and increase heat to high. Bring to a boil, then reduce to medium-low so it's simmering. Cook for 8-10 minutes, stirring well after the first 5 minutes.
Meanwhile, chop peppers* and grate 1/2 cup of cheese***.
After 8 minutes, check pasta. If it is almost done, add peppers and cook for another 1-2 minutes (I like vegetables that still have some of their firmness and texture).
Add grated cheese and ranch dressing. Stir well to combine. Taste and add more Sriracha if you would like it spicier (it should be pretty mild if you started with 1 tablespoon).
Garnish with fresh parsley (optional) and enjoy (while also enjoying the lack of dishes you'll have to do)!