Rehydrate Dried Shiitake Mushrooms in 1 ½ cups of hot water for 20-30 minutes. Strain out the mushrooms and set the mushroom soaking liquid aside.
Press the Sauté button. Wait until the screen says HOT. Pour 1 tbsp olive oil and 1 tbsp unsalted butter in the Instant Pot. Add in sliced shiitake mushrooms and oyster mushrooms. Let the mushroom broth evaporate completely then season with 2 tbsp (30ml) regular soy sauce and stir occasionally until mushrooms are slightly crisped and browned.
Combine 1 tbsp (15ml) regular soy sauce, 3 cups (750ml) unsalted chicken stock, and 1 cup (250ml) of the mushroom soaking liquid together.
Sauté Onions & Garlic: Add diced onions & shallots, then saute until softened and fragrant. Add in minced garlic, then saute until fragrant.
Add Rice and Season: Add 1 tbsp (15ml) olive oil & another 2 tbsp (29g) unsalted butter to the empty half of the pot. Add 2 cups (400g) arborio rice in the oil. Stir until the rice is evenly coated with the oil. Add sliced shiitake mushrooms and mix well with the rice.
Deglaze: Pour in ¾ cup (188ml) white wine, fully deglaze the bottom of the pot with a wooden spoon. Stir and let the wine boil for roughly a minute allowing the alcohol to evaporate.
Pressure Cook Risotto: Pour 4 cups (1L) mushroom chicken stock in the pressure cooker. Now is a good time to make sure no rice or onion pieces stick to the sides of the pot. Close lid and pressure cook at High Pressure for 5 minutes + Quick Release. Open the lid carefully.
Reduce Risotto: Your pressure cooked risotto should look runny. Stir to combine with a silicone spatula to form a creamy and smooth consistency. If it is too runny, stir and cook for another few minutes over medium heat (Instant Pot: press Sauté button). Add in 20g Parmesan cheese. Mix well. Taste and season with kosher salt and black pepper.
Serve: Garnish with freshly chopped parsley. Serve immediately with more Parmesan cheese