Select the sauté function on Instant Pot. Add butter. When melted, add onions and cook, stirring occasionally until onions begin to soften, 3 to 4 minutes. Add garlic; cook until fragrant, about 30 seconds. Add mushrooms; cook 3 to 4 minutes. Add rice; stir to coat. Cook until opaque, about 1 minute.
Stir in the Vermouth or wine; cook until most of the liquid has evaporated, 3 to 4 minutes.
Add salt, pepper, thyme, and chicken broth; stir to combine. Secure the lid on the Instant Pot and ensure that the vent is closed. Program on high pressure for 6 minutes.
Quick release pressure and carefully remove the lid. The mixture will still be soupy.
Select the sauté function. Stir risotto with a wooden spoon for 2 to 3 minutes or until creamy.
Add cream and Parmesan cheese; stir until cheese has melted.
Add green peas; stir to combine.
Garnish with minced parsley, sliced green onions, or chopped chives.
Yield: 4 to 6 servings.