Start the Instant Pot on SAUTE mode and add the oil. Once oil is heated, add mushrooms, broccoli and garlic. Sprinkle a pinch of salt and let them cook until mushrooms start to release the water. (3-5 minutes)
Once mushrooms have browned, add baby spinach and mix well. Cancel SAUTE. Remove cookedvegetables and set them aside.
Add water and deglaze the pot by scrapping the bits stuck at the bottom. Make sure nothing is stuck at the base. Add pasta, enough
water to cover the pasta (about 2 cups..do NOT push the pasta down under water)
Add some salt and remaining olive oil. Close the lid. Valve at SEALING.
Check the cooking time mentioned on the pasta box. Now press MANUAL or PRESSURE COOK and choose half of the cooking time suggested on the box. (usually 4-5 minutes)
Once Instant Pot finishes cooking and goes to KEEP WARM timer, wait for 5 minutes and then release the leftover pressure by moving the valve from SEALING to VENTING. After the silver pin drops, open the lid.
Stir in sautéed vegetables and pesto sauce. Add salt and pepper. Gently mix everything well together. Garnish with fresh chopped basil, red chili flakes and black pepper and nutritional yeast (or parmesan if using) and serve. Bon Appetit !