Brown Sausage: Dice the sausages into discs/rings. Set Instant Pot on SAUTE function and set it on HIGH heat. Add 2 tbsp oil, when the oil becomes hot gently release the sausages and brown them (around the edges) both sides. Set them aside.
Saute Shrimp: In the same pot gently release the thawed de-shelled, de-veined shrimp (we kept the tails intact for more flavor) and saute them lightly just until pink. Set them aside.
Saute Holy Trinity & seasonings: Now, add 2 tbsp oil and add the onion, garlic & celery. Saute them well until the onion and celery begins to turn limp. Add salt according to your taste to quicken the process of sautéing. Next, add the bell peppers and saute for another 1 min. Than add the seasonings like cajun/creole, cayenne, oregano & black pepper and saute well for 1-2 min.
De-glaze pot: Pour the chicken stock and de-glaze the pot very well scraping the sides and the bottom of the pot with the help of a spatula. This will help loosen any stuck food particles and help prevent the BURN error! DO NOT rush this step, there should not be any food particles (even tiny amount) stuck at the bottom of the pot. Add the Worcestershire sauce & mix well (in the recipe video I forgot to add it now & instead added it after adding the crushed tomatoes.) TURN OFF the SAUTE function.
Layer Ingredients: Transfer the sausages into the pot, spread them out with the help of a spatula. Now, add rinsed long grain white rice (rinsed very well until clear water runs through & drained well with a colander). Gently spread out the rice with the help of spatula and press it down to cover it as much as you can with the liquid. DO NOT stir or mix. Add the crushed tomatoes on top of the rice layer and spread it out so that the rice is fully covered with the tomatoes. DO NOT stir or mix.
Pressure Cook: Now, secure the lid of the instant pot, seal the valve and pressure cook on HIGH for just 6 mins. Once the pressure cooking cycle is over the instant pot will begin to beep. Wait for 10 mins natural pressure release and than release the rest of the pressure manually by moving the valve from the sealing to the venting position. Open the lid carefully only when the metal pin on the lid drops.
Fluff Rice: Gently fluff the cooked rice with the help of a pair of forks. This will also help to incorporate all ingredients in the pot and blend the flavors. At this stage the rice will be more moist, that's perfect, as you rest the Jambalaya for another 5-10 mins it'll attain the perfect texture and consistency. Add the sauteed shrimp and gently mix it with the Jambalaya.
Serve Jambalaya: Allow the Jambalaya to rest for another 5-10 mins. This will help marry the flavors. Garnish with chopped green onion (scallion) and serve. Enjoy!