Brown Sausage: Set instant pot on SAUTE (high heat), add oil and when the oil becomes moderately hot gently release the ground Italian sausage and brown the meat nicely stirring and breaking down the sausage with the help of your spatula. It might release some amount of fat, if you prefer you may drain out the excess fat.
Saute aromatics & add wine: Now, throw in the chopped onion, red bell pepper & minced garlic and saute for couple of mins. Pour the white wine and deglaze the pot by scraping the bottom & the sides of the pot, this will also give the alcohol a chance to evaporate and cook down & it'll infuse the dish with the best flavors.
Saute seasonings: Add all the seasonings mentioned above in the "Seasonings" section of the ingredient list. Also add salt according to your personal taste preference and saute for couple of mins. This will help release the essential oils from the seasonings and massive flavors.
Deglaze pot: Pour the chicken stock (water + better than bouillon mixed well) and deglaze the pot very well scraping the bottom and the sides of the pot with the help of a spatula. This will help loosen any stuck food particles & prevent the BURN error. CANCEL the SAUTE function.
Layer pasta & sauce: Dump the uncooked penne pasta, spread the pasta in a single layer on top of the sausage & the liquid with the help of a spatula. DO NOT stir or mix. Pour the tomato passata all over the pasta and gently press down the pasta with the help of a spatula just to make sure that they get a good coat with the liquid. DO NOT mix or stir anything in the pot.
Pressure Cook: Secure the lid and PRESSURE COOK on HIGH for just 4 mins for al dente pasta and for 6 mins for soft pasta. Once the cooking cycle is over the instant pot will begin to beep. Perform a quick pressure release immediately by manually moving the valve from the sealing to the venting position. Open the lid carefully when the metal pin on top of the lid drops.
Add dairy: Now, give everything in the pot a good stir. This will help mix all the cooked ingredients well. Warm up the fridge cold milk and the heavy whipping cream slightly in the microwave oven and than add them in the instant pot. Mix well. At this stage you can control the consistency. If you prefer soupy pasta add more milk or stock at this stage and mix well. We prefer a good sauce but not soupy pasta. Throw in the parmesan cheese & mix well until the cheese melts.
Serve Sausage Pasta: Now, add the baby spinach and stir to mix well. The residual heat will wilt the spinach leaves and perfectly cook them down without making them overtly mushy. Serve the instant pot creamy sausage pasta warm or hot and enjoy!