Using the Sauté function, heat butter until it melts. Once melted, add the minced onions and sauté until the onions begin to soften, about 2-3 minutes.
Add the mushrooms to the onion mixture and continue to sauté the mixture for 2-3 minutes, until the mushrooms soften. Add the garlic and sauté for 30-60 seconds, just until fragrant. Turn off the sauté function by hitting Cancel.
Add the beef broth and use a wooden spoon or spatula to scrape up any browned bits on the bottom of the inner pot.
Stir in the dried onion flakes, onion powder, garlic powder, celery seed, pepper, dried parsley, kosher salt, and Worcestershire Sauce.
Place the rice into a fine-mesh strainer and rinse really well. Once rinsed, add the rice into the inner pot and gently push the rice down so that it is fully submerged in the broth.
Place the lid on the pressure cooker and seal the vent knob. Set to cook on high pressure for 3 minutes for white rice and 22 minutes for brown rice.
Once the cooking time has elapsed, allow the pressure to release naturally for at least 10 minutes, before attempting to do a quick release of pressure.
Once the pressure is released, open up the inner pot and fluff the mixture with a fork. Serve immediately with a sprinkling of fresh parsley if desired.
Video
Notes
Stock/Broth: Use beef broth, chicken stock, OR vegetable broth.Storage: Let cool slightly, transfer to an airtight container, and refrigerate for up to 3 days, or freeze in a freezer-safe container for up to 3 months. High Altitude: Increase the cook time per my Instant Pot high altitude conversion chart and add 1-2 tablespoons of extra liquid per cup of rice.Reheating: Defrost overnight in the refrigerator if needed. Then transfer to a heat-safe container, add a splash of additional broth or water to the rice, cover with a moistened paper towel, and heat in the microwave until warmed through. (The water and towel will help prevent the rice from drying out.)Dairy-Free Modification: Use extra virgin olive oil in place of butter.Gluten-Free Modification: Use gluten-free broth and Worcestershire sauce.