Sear Chicken: Season chicken with ½ tsp paprika, crushed black pepper & 1-2 pinches salt, rub well. Marinate chicken for 30 mins. Now, set Instant Pot on SAUTE function & set it on HIGH heat. Add olive oil & butter & allow to become hot. Gently release the marinated chicken (skin side down) & sear until golden brown. Set them aside.
Saute aromatics: In the same pot release the sliced onion and saute for 1 min. Add salt, this will soften the onions faster. Add minced garlic & saute another 1 min. Next, add 1 tsp paprika, stir to mix well. Add the sundried tomatoes and saute for 30 seconds.
De-glaze pot: Now, pour the white wine & de-glaze the pot very well scraping the sides & the bottom of the pot. This will help loosen any stuck food particles & prevent the BURN error! Cook down the wine for 30 secs. Than, add the chicken stock or water + bouillon paste (refer ingredients above) and mix well. CANCEL the SAUTE function.
Pressure cook chicken: Transfer back the seared chicken thighs into the pot and lay them in a single layer on top of the onions. DO NOT mix or stir. Secure the lid, seal the valve and PRESSURE COOK on HIGH for 7 mins. Once, the pressure cooking cycle is over the instant pot will begin to beep. Wait for 5 mins natural pressure release, than release the rest of the pressure manually by moving the valve from the sealing to the venting position. Open the lid carefully. Fish out the chicken. CANCEL the pressure cook function.
Make creamy sauce: Add the sliced bell peppers (the residual heat will cook down the peppers), crushed black pepper and slightly warm heavy whipping cream. Stir to mix well. Now, add the grated parmesan cheese and stir briskly until the cheese completely melts. Make sure the instant pot is turned off, otherwise the cheese will clump up. Once the cheese has melted hit back the SAUTE function & set it on LOW heat. Add the corn starch slurry, mix well. Simmer the sauce on low until it thickens to your desired consistency. TURN OFF the instant pot.
Serve Tuscan chicken: Now, add the baby spinach and stir to mix well. The residual heat will perfectly wilt the leaves. Transfer back the chicken into the pot. Check for seasoning, if need be add a little more salt to open up the flavors. Smother the chicken with the creamy sauce. Rest the dish for 5 mins and serve hot. Enjoy!