Let your Instant Pot preheat on the Sauté mode.
Add 2 tbsp. (1 fl oz / 30ml) of avocado oil and 1 pound (16 oz / 454g) of sliced white mushrooms to the pot, sautéing them for 5 minutes.
Stir in the remaining ingredients: 0. 25 cup (2 fl oz / 59ml) chicken stock, 1 cup (4 oz / 113g) sliced radishes, 1 tbsp. (0. 1 oz / 3g) chopped parsley, 2 tbsp. (1 fl oz / 30ml) balsamic vinegar, and 0. 1 tsp. (0. 02 oz / 0. 5g) of salt and black pepper, ensuring everything is mixed well.
Seal the Instant Pot’s lid securely and set it to cook for 10 minutes on Manual mode at High pressure.
Allow the pressure to release naturally for 10 minutes, then carefully remove the lid.
Sear, Don't Steam: During the 5-minute sauté step, let the mushrooms sit undisturbed in the hot avocado oil for the first minute or two. This helps them develop a beautiful, savory crust rather than just releasing their water and steaming.
Don't Skip the Garnish: The fresh chopped parsley isn't just for looks. Its bright, peppery notes cut right through the rich umami of the mushrooms and chicken stock, perfectly balancing the final dish.