Add olive oil to Instant Pot and select the Sauté function. Set to high and once the display reads “hot,” add carrots, red onion, celery, Portobello mushrooms, and minced garlic. Season with salt and black pepper, to taste, and cook, stirring continually, until the veggies soften and the mushrooms start to release their liquid, approximately 5 minutes. Turn unit off.
Add wild rice, broth, and fresh rosemary and stir to combine. Season with additional salt and black pepper, if desired.
Add the lid and set the pressure valve to “sealing.” Select the “Manual” cooking option on the high setting and set cook time to 15 minutes. When done cooking, allow the pressure to release naturally for 10 minutes, and then do a quick release for any remaining pressure. Turn the unit off and let sit for 5 additional minutes.
Remove lid and fluff the rice with a fork while stirring in one tablespoon fresh parsley. Serve immediately with the remaining chopped parsley on top. Enjoy!