Whisk half-and-half, 1/4 cup broth, cornstarch, Worcestershire sauce, salt, and pepper together in a bowl. Set soup mixture aside.
Turn on a multi-functional pressure cooker (such as Instant Pot®) and select Saute function. Add oil, butter, and onions. Cook for 2 minutes. Add mushrooms and 1/4 cup broth; cook 3 minutes more. Turn pot off.
Add soup mixture, green beans, 1/2 cup crispy onions, and remaining 1/4 cup broth. Stir to combine. Close and lock the lid, select manual and set timer for 1 minute. Allow 10 minutes for pressure to build.
Release pressure using the natural-release method according to manufacturer's instructions, about 5 minutes. Carefully release remaining pressure manually. Remove lid and transfer green bean mixture to a serving dish. Let sit to thicken, about 5 minutes. Top with remaining crispy onions.
Nutritional Facts
Per 6 servings
Calories: 320
Carbohydrate: 25g
Fat: 23g
Fiber: 3g
Protein: 4g
Sugar: 3g
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